roger-hiro / blogfn Goto Github PK

const all = (arr, fn = Boolean) => arr.every(fn);

all([4, 2, 3], x => x > 1); // true
all([1, 2, 3]); // true

const allEqual = arr => arr.every(val => val === arr[0]);

allEqual([1, 2, 3, 4, 5, 6]); // false
allEqual([1, 1, 1, 1]); // true

const approximatelyEqual = (v1, v2, epsilon = 0.001) => Math.abs(v1 - v2) < epsilon;

approximatelyEqual(Math.PI / 2.0, 1.5708); // true

const arrayToCSV = (arr, delimiter = ',') =>
  arr.map(v => v.map(x => `"${x}"`).join(delimiter)).join('\n');
  
arrayToCSV([['a', 'b'], ['c', 'd']]); // '"a","b"\n"c","d"'
arrayToCSV([['a', 'b'], ['c', 'd']], ';'); // '"a";"b"\n"c";"d"'

const arrayToHtmlList = (arr, listID) =>
  (el => (
    (el = document.querySelector('#' + listID)),
    (el.innerHTML += arr.map(item => `<li>${item}</li>`).join(''))
  ))();
  
arrayToHtmlList(['item 1', 'item 2'], 'myListID');

const average = (...nums) => nums.reduce((acc, val) => acc + val, 0) / nums.length;
average(...[1, 2, 3]); // 2
average(1, 2, 3); // 2

const averageBy = (arr, fn) =>
  arr.map(typeof fn === 'function' ? fn : val => val[fn]).reduce((acc, val) => acc + val, 0) /
  arr.length;
  
averageBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], o => o.n); // 5
averageBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], 'n'); // 5

const bifurcate = (arr, filter) =>
  arr.reduce((acc, val, i) => (acc[filter[i] ? 0 : 1].push(val), acc), [[], []]);
bifurcate(['beep', 'boop', 'foo', 'bar'], [true, true, false, true]); 
// [ ['beep', 'boop', 'bar'], ['foo'] ]

const castArray = val => (Array.isArray(val) ? val : [val]);

castArray('foo'); // ['foo']
castArray([1]); // [1]
castArray(1); // [1]

const compact = arr => arr.filter(Boolean);

compact([0, 1, false, 2, '', 3, 'a', 'e' * 23, NaN, 's', 34]); 
// [ 1, 2, 3, 'a', 's', 34 ]

const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a), 0);
countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3

const deepFlatten = arr => [].concat(...arr.map(v => (Array.isArray(v) ? deepFlatten(v) : v)));

deepFlatten([1, [2], [[3], 4], 5]); // [1,2,3,4,5]

const difference = (a, b) => {
  const s = new Set(b);
  return a.filter(x => !s.has(x));
};

difference([1, 2, 3], [1, 2, 4]); // [3]

const differenceBy = (a, b, fn) => {
  const s = new Set(b.map(fn));
  return a.filter(x => !s.has(fn(x)));
};

differenceBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [1.2]
differenceBy([{ x: 2 }, { x: 1 }], [{ x: 1 }], v => v.x); // [ { x: 2 } ]

const dropWhile = (arr, func) => {
  while (arr.length > 0 && !func(arr[0])) arr = arr.slice(1);
  return arr;
};

dropWhile([1, 2, 3, 4], n => n >= 3); // [3,4]

const flatten = (arr, depth = 1) =>
  arr.reduce((a, v) => a.concat(depth > 1 && Array.isArray(v) ? flatten(v, depth - 1) : v), []);

flatten([1, [2], 3, 4]); // [1, 2, 3, 4]
flatten([1, [2, [3, [4, 5], 6], 7], 8], 2); // [1, 2, 3, [4, 5], 6, 7, 8]

const indexOfAll = (arr, val) => arr.reduce((acc, el, i) => (el === val ? [...acc, i] : acc), []);

indexOfAll([1, 2, 3, 1, 2, 3], 1); // [0,3]
indexOfAll([1, 2, 3], 4); // []

const intersection = (a, b) => {
  const s = new Set(b);
  return a.filter(x => s.has(x));
};

intersection([1, 2, 3], [4, 3, 2]); // [2, 3]

const intersectionBy = (a, b, fn) => {
  const s = new Set(b.map(fn));
  return a.filter(x => s.has(fn(x)));
};

intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [2.1]

const intersectionWith = (a, b, comp) => a.filter(x => b.findIndex(y => comp(x, y)) !== -1);

intersectionWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0, 3.9], (a, b) => Math.round(a) === Math.round(b)); // [1.5, 3, 0]

const minN = (arr, n = 1) => [...arr].sort((a, b) => a - b).slice(0, n);

minN([1, 2, 3]); // [1]
minN([1, 2, 3], 2); // [1,2]

const negate = func => (...args) => !func(...args);

[1, 2, 3, 4, 5, 6].filter(negate(n => n % 2 === 0)); // [ 1, 3, 5 ]

const randomIntArrayInRange = (min, max, n = 1) =>
  Array.from({ length: n }, () => Math.floor(Math.random() * (max - min + 1)) + min);
  
randomIntArrayInRange(12, 35, 10); // [ 34, 14, 27, 17, 30, 27, 20, 26, 21, 14 ]

const sample = arr => arr[Math.floor(Math.random() * arr.length)];

sample([3, 7, 9, 11]); // 9

const sampleSize = ([...arr], n = 1) => {
  let m = arr.length;
  while (m) {
    const i = Math.floor(Math.random() * m--);
    [arr[m], arr[i]] = [arr[i], arr[m]];
  }
  return arr.slice(0, n);
};

sampleSize([1, 2, 3], 2); // [3,1]
sampleSize([1, 2, 3], 4); // [2,3,1]

const shuffle = ([...arr]) => {
  let m = arr.length;
  while (m) {
    const i = Math.floor(Math.random() * m--);
    [arr[m], arr[i]] = [arr[i], arr[m]];
  }
  return arr;
};

const foo = [1, 2, 3];
shuffle(foo); // [2, 3, 1], foo = [1, 2, 3]

const nest = (items, id = null, link = 'parent_id') =>
  items
    .filter(item => item[link] === id)
    .map(item => ({ ...item, children: nest(items, item.id) }));

const comments = [
  { id: 1, parent_id: null },
  { id: 2, parent_id: 1 },
  { id: 3, parent_id: 1 },
  { id: 4, parent_id: 2 },
  { id: 5, parent_id: 4 }
];
const nestedComments = nest(comments); // [{ id: 1, parent_id: null, children: [...] }]

onst attempt = (fn, ...args) => {
  try {
    return fn(...args);
  } catch (e) {
    return e instanceof Error ? e : new Error(e);
  }
};
var elements = attempt(function(selector) {
  return document.querySelectorAll(selector);
}, '>_>');
if (elements instanceof Error) elements = []; // elements = []

const defer = (fn, ...args) => setTimeout(fn, 1, ...args);

defer(console.log, 'a'), console.log('b'); // logs 'b' then 'a'

const runPromisesInSeries = ps => ps.reduce((p, next) => p.then(next), Promise.resolve());
const delay = d => new Promise(r => setTimeout(r, d));

runPromisesInSeries([() => delay(1000), () => delay(2000)]);
//依次执行每个Promises ，总共需要3秒钟才能完成

const timeTaken = callback => {
  console.time('timeTaken');
  const r = callback();
  console.timeEnd('timeTaken');
  return r;
};

timeTaken(() => Math.pow(2, 10)); // 1024, (logged): timeTaken: 0.02099609375ms

const createEventHub = () => ({
  hub: Object.create(null),
  emit(event, data) {
    (this.hub[event] || []).forEach(handler => handler(data));
  },
  on(event, handler) {
    if (!this.hub[event]) this.hub[event] = [];
    this.hub[event].push(handler);
  },
  off(event, handler) {
    const i = (this.hub[event] || []).findIndex(h => h === handler);
    if (i > -1) this.hub[event].splice(i, 1);
    if (this.hub[event].length === 0) delete this.hub[event];
  }
});

const handler = data => console.log(data);
const hub = createEventHub();
let increment = 0;

// 订阅，监听不同事件
hub.on('message', handler);
hub.on('message', () => console.log('Message event fired'));
hub.on('increment', () => increment++);

// 发布：发出事件以调用所有订阅给它们的处理程序，并将数据作为参数传递给它们
hub.emit('message', 'hello world'); // 打印 'hello world' 和 'Message event fired'
hub.emit('message', { hello: 'world' }); // 打印 对象 和 'Message event fired'
hub.emit('increment'); // increment = 1

// 停止订阅
hub.off('message', handler);

const memoize = fn => {
  const cache = new Map();
  const cached = function(val) {
    return cache.has(val) ? cache.get(val) : cache.set(val, fn.call(this, val)) && cache.get(val);
  };
  cached.cache = cache;
  return cached;
};

/**
 * Create a cached version of a pure function.
 */
export function cached<F: Function> (fn: F): F {
  const cache = Object.create(null)
  return (function cachedFn (str: string) {
    const hit = cache[str]
    return hit || (cache[str] = fn(str))
  }: any)
}

const once = fn => {
  let called = false
  return function () {
    if (!called) {
      called = true
      fn.apply(this, arguments)
    }
  }
};

const flattenObject = (obj, prefix = '') =>
  Object.keys(obj).reduce((acc, k) => {
    const pre = prefix.length ? prefix + '.' : '';
    if (typeof obj[k] === 'object') Object.assign(acc, flattenObject(obj[k], pre + k));
    else acc[pre + k] = obj[k];
    return acc;
  }, {});
  
flattenObject({ a: { b: { c: 1 } }, d: 1 }); // { 'a.b.c': 1, d: 1 }

const unflattenObject = obj =>
  Object.keys(obj).reduce((acc, k) => {
    if (k.indexOf('.') !== -1) {
      const keys = k.split('.');
      Object.assign(
        acc,
        JSON.parse(
          '{' +
            keys.map((v, i) => (i !== keys.length - 1 ? `"${v}":{` : `"${v}":`)).join('') +
            obj[k] +
            '}'.repeat(keys.length)
        )
      );
    } else acc[k] = obj[k];
    return acc;
  }, {});
  
unflattenObject({ 'a.b.c': 1, d: 1 }); // { a: { b: { c: 1 } }, d: 1 }

const byteSize = str => new Blob([str]).size;

byteSize('😀'); // 4
byteSize('Hello World'); // 11

const capitalize = ([first, ...rest]) =>
  first.toUpperCase() + rest.join('');
  
capitalize('fooBar'); // 'FooBar'
capitalize('fooBar', true); // 'Foobar'

const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase());

capitalizeEveryWord('hello world!'); // 'Hello World!'

const decapitalize = ([first, ...rest]) =>
  first.toLowerCase() + rest.join('')

decapitalize('FooBar'); // 'fooBar'
decapitalize('FooBar'); // 'fooBar'

const luhnCheck = num => {
  let arr = (num + '')
    .split('')
    .reverse()
    .map(x => parseInt(x));
  let lastDigit = arr.splice(0, 1)[0];
  let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val * 2) % 9) || 9), 0);
  sum += lastDigit;
  return sum % 10 === 0;
};

luhnCheck('4485275742308327'); // true
luhnCheck(6011329933655299); //  false
luhnCheck(123456789); // false

const splitLines = str => str.split(/\r?\n/);

splitLines('This\nis a\nmultiline\nstring.\n'); // ['This', 'is a', 'multiline', 'string.' , '']

const stripHTMLTags = str => str.replace(/<[^>]*>/g, '');

stripHTMLTags('<p><em>lorem</em> <strong>ipsum</strong></p>'); // 'lorem ipsum'

const dayOfYear = date =>
  Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);

dayOfYear(new Date()); // 285

const forOwn = (obj, fn) => Object.keys(obj).forEach(key => fn(obj[key], key, obj));
forOwn({ foo: 'bar', a: 1 }, v => console.log(v)); // 'bar', 1

const getColonTimeFromDate = date => date.toTimeString().slice(0, 8);

getColonTimeFromDate(new Date()); // "08:38:00"

const getDaysDiffBetweenDates = (dateInitial, dateFinal) =>
  (dateFinal - dateInitial) / (1000 * 3600 * 24);
  
getDaysDiffBetweenDates(new Date('2019-01-01'), new Date('2019-10-14')); // 286

const is = (type, val) => ![, null].includes(val) && val.constructor === type;

is(Array, [1]); // true
is(ArrayBuffer, new ArrayBuffer()); // true
is(Map, new Map()); // true
is(RegExp, /./g); // true
is(Set, new Set()); // true
is(WeakMap, new WeakMap()); // true
is(WeakSet, new WeakSet()); // true
is(String, ''); // true
is(String, new String('')); // true
is(Number, 1); // true
is(Number, new Number(1)); // true
is(Boolean, true); // true
is(Boolean, new Boolean(true)); // true

const isAfterDate = (dateA, dateB) => dateA > dateB;

isAfterDate(new Date(2010, 10, 21), new Date(2010, 10, 20)); // true

const isBeforeDate = (dateA, dateB) => dateA < dateB;

isBeforeDate(new Date(2010, 10, 20), new Date(2010, 10, 21)); // true

const tomorrow = () => {
  let t = new Date();
  t.setDate(t.getDate() + 1);
  return t.toISOString().split('T')[0];
};

tomorrow(); // 2019-10-15 (如果明天是2019-10-15)

const equals = (a, b) => {
  if (a === b) return true;
  if (a instanceof Date && b instanceof Date) return a.getTime() === b.getTime();
  if (!a || !b || (typeof a !== 'object' && typeof b !== 'object')) return a === b;
  if (a.prototype !== b.prototype) return false;
  let keys = Object.keys(a);
  if (keys.length !== Object.keys(b).length) return false;
  return keys.every(k => equals(a[k], b[k]));
};

equals({ a: [2, { e: 3 }], b: [4], c: 'foo' }, { a: [2, { e: 3 }], b: [4], c: 'foo' }); // true

const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;

randomIntegerInRange(0, 5); // 3

const randomNumberInRange = (min, max) => Math.random() * (max - min) + min;

randomNumberInRange(2, 10); // 6.0211363285087005

const round = (n, decimals = 0) => Number(`${Math.round(`${n}e${decimals}`)}e-${decimals}`);

round(1.005, 2); // 1.01

const sum = (...arr) => [...arr].reduce((acc, val) => acc + val, 0);

sum(1, 2, 3, 4); // 10
sum(...[1, 2, 3, 4]); // 10

const toCurrency = (n, curr, LanguageFormat = undefined) =>
  Intl.NumberFormat(LanguageFormat, { style: 'currency', currency: curr }).format(n);
  
toCurrency(123456.789, 'EUR'); // €123,456.79
toCurrency(123456.789, 'USD', 'en-us'); // $123,456.79  
toCurrency(123456.789, 'USD', 'fa'); // ۱۲۳٬۴۵۶٫۷۹
toCurrency(322342436423.2435, 'JPY'); // ¥322,342,436,423 

const bottomVisible = () =>
  document.documentElement.clientHeight + window.scrollY >=
  (document.documentElement.scrollHeight || document.documentElement.clientHeight);

bottomVisible(); // true

const fs = require('fs');
const createDirIfNotExists = dir => (!fs.existsSync(dir) ? fs.mkdirSync(dir) : undefined);
createDirIfNotExists('test'); 

const currentURL = () => window.location.href;

currentURL(); // 'https://juejin.im'

const distance = (x0, y0, x1, y1) => Math.hypot(x1 - x0, y1 - y0);

distance(1, 1, 2, 3); // 2.23606797749979

const elementContains = (parent, child) => parent !== child && parent.contains(child);

elementContains(document.querySelector('head'), document.querySelector('title')); // true
elementContains(document.querySelector('body'), document.querySelector('body')); // false

const getStyle = (el, ruleName) => getComputedStyle(el)[ruleName];

getStyle(document.querySelector('p'), 'font-size'); // '16px'

const getType = v =>
  v === undefined ? 'undefined' : v === null ? 'null' : v.constructor.name.toLowerCase();
  
getType(new Set([1, 2, 3])); // 'set'
getType([1, 2, 3]); // 'array'

const hasClass = (el, className) => el.classList.contains(className);
hasClass(document.querySelector('p.special'), 'special'); // true

const hide = (...el) => [...el].forEach(e => (e.style.display = 'none'));

hide(document.querySelectorAll('img')); // 隐藏所有<img>标签

const httpsRedirect = () => {
  if (location.protocol !== 'https:') location.replace('https://' + location.href.split('//')[1]);
};

httpsRedirect(); // 若在`http://www.baidu.com`, 则跳转到`https://www.baidu.com`

const insertAfter = (el, htmlString) => el.insertAdjacentHTML('afterend', htmlString);

// <div id="myId">...</div> <p>after</p>
insertAfter(document.getElementById('myId'), '<p>after</p>'); 

const insertBefore = (el, htmlString) => el.insertAdjacentHTML('beforebegin', htmlString);

insertBefore(document.getElementById('myId'), '<p>before</p>'); // <p>before</p> <div id="myId">...</div>

const isBrowser = () => ![typeof window, typeof document].includes('undefined');

isBrowser(); // true (browser)
isBrowser(); // false (Node)

const isBrowserTabFocused = () => !document.hidden;

isBrowserTabFocused(); // true

const nodeListToArray = nodeList => [...nodeList];

nodeListToArray(document.childNodes); // [ <!DOCTYPE html>, html ]

const randomHexColorCode = () => {
  let n = (Math.random() * 0xfffff * 1000000).toString(16);
  return '#' + n.slice(0, 6);
};

randomHexColorCode(); // "#e34155"

const scrollToTop = () => {
  const c = document.documentElement.scrollTop || document.body.scrollTop;
  if (c > 0) {
    window.requestAnimationFrame(scrollToTop);
    window.scrollTo(0, c - c / 8);
  }
};

scrollToTop();

const smoothScroll = element =>
  document.querySelector(element).scrollIntoView({
    behavior: 'smooth'
  });
  
smoothScroll('#fooBar'); 
smoothScroll('.fooBar'); 

const detectDeviceType = () =>
  /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent)
    ? 'Mobile'
    : 'Desktop';

const getScrollPosition = (el = window) => ({
  x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft,
  y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop
});

getScrollPosition(); // {x: 0, y: 200}

const size = val =>
  Array.isArray(val)
    ? val.length
    : val && typeof val === 'object'
    ? val.size || val.length || Object.keys(val).length
    : typeof val === 'string'
    ? new Blob([val]).size
    : 0;

size([1, 2, 3, 4, 5]); // 5
size('size'); // 4
size({ one: 1, two: 2, three: 3 }); // 3

const escapeHTML = str =>
  str.replace(
    /[&<>'"]/g,
    tag =>
      ({
        '&': '&amp;',
        '<': '&lt;',
        '>': '&gt;',
        "'": '&#39;',
        '"': '&quot;'
      }[tag] || tag)
  );

escapeHTML('<a href="#">Me & you</a>'); // '&lt;a href=&quot;#&quot;&gt;Me &amp; you&lt;/a&gt;'

const all = (arr, fn = Boolean) => arr.every(fn);

all([4, 2, 3], x => x > 1); // true
all([1, 2, 3]); // true

const allEqual = arr => arr.every(val => val === arr[0]);

allEqual([1, 2, 3, 4, 5, 6]); // false
allEqual([1, 1, 1, 1]); // true

const approximatelyEqual = (v1, v2, epsilon = 0.001) => Math.abs(v1 - v2) < epsilon;

approximatelyEqual(Math.PI / 2.0, 1.5708); // true

const arrayToCSV = (arr, delimiter = ',') =>
  arr.map(v => v.map(x => `"${x}"`).join(delimiter)).join('\n');
  
arrayToCSV([['a', 'b'], ['c', 'd']]); // '"a","b"\n"c","d"'
arrayToCSV([['a', 'b'], ['c', 'd']], ';'); // '"a";"b"\n"c";"d"'

const arrayToHtmlList = (arr, listID) =>
  (el => (
    (el = document.querySelector('#' + listID)),
    (el.innerHTML += arr.map(item => `<li>${item}</li>`).join(''))
  ))();
  
arrayToHtmlList(['item 1', 'item 2'], 'myListID');

const average = (...nums) => nums.reduce((acc, val) => acc + val, 0) / nums.length;
average(...[1, 2, 3]); // 2
average(1, 2, 3); // 2

const averageBy = (arr, fn) =>
  arr.map(typeof fn === 'function' ? fn : val => val[fn]).reduce((acc, val) => acc + val, 0) /
  arr.length;
  
averageBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], o => o.n); // 5
averageBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], 'n'); // 5

const bifurcate = (arr, filter) =>
  arr.reduce((acc, val, i) => (acc[filter[i] ? 0 : 1].push(val), acc), [[], []]);
bifurcate(['beep', 'boop', 'foo', 'bar'], [true, true, false, true]); 
// [ ['beep', 'boop', 'bar'], ['foo'] ]

const castArray = val => (Array.isArray(val) ? val : [val]);

castArray('foo'); // ['foo']
castArray([1]); // [1]
castArray(1); // [1]

const compact = arr => arr.filter(Boolean);

compact([0, 1, false, 2, '', 3, 'a', 'e' * 23, NaN, 's', 34]); 
// [ 1, 2, 3, 'a', 's', 34 ]

const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a), 0);
countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3

const deepFlatten = arr => [].concat(...arr.map(v => (Array.isArray(v) ? deepFlatten(v) : v)));

deepFlatten([1, [2], [[3], 4], 5]); // [1,2,3,4,5]

const difference = (a, b) => {
  const s = new Set(b);
  return a.filter(x => !s.has(x));
};

difference([1, 2, 3], [1, 2, 4]); // [3]

const differenceBy = (a, b, fn) => {
  const s = new Set(b.map(fn));
  return a.filter(x => !s.has(fn(x)));
};

differenceBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [1.2]
differenceBy([{ x: 2 }, { x: 1 }], [{ x: 1 }], v => v.x); // [ { x: 2 } ]

const dropWhile = (arr, func) => {
  while (arr.length > 0 && !func(arr[0])) arr = arr.slice(1);
  return arr;
};

dropWhile([1, 2, 3, 4], n => n >= 3); // [3,4]

const flatten = (arr, depth = 1) =>
  arr.reduce((a, v) => a.concat(depth > 1 && Array.isArray(v) ? flatten(v, depth - 1) : v), []);

flatten([1, [2], 3, 4]); // [1, 2, 3, 4]
flatten([1, [2, [3, [4, 5], 6], 7], 8], 2); // [1, 2, 3, [4, 5], 6, 7, 8]

const indexOfAll = (arr, val) => arr.reduce((acc, el, i) => (el === val ? [...acc, i] : acc), []);

indexOfAll([1, 2, 3, 1, 2, 3], 1); // [0,3]
indexOfAll([1, 2, 3], 4); // []

const intersection = (a, b) => {
  const s = new Set(b);
  return a.filter(x => s.has(x));
};

intersection([1, 2, 3], [4, 3, 2]); // [2, 3]

const intersectionBy = (a, b, fn) => {
  const s = new Set(b.map(fn));
  return a.filter(x => s.has(fn(x)));
};

intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [2.1]

const intersectionWith = (a, b, comp) => a.filter(x => b.findIndex(y => comp(x, y)) !== -1);

intersectionWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0, 3.9], (a, b) => Math.round(a) === Math.round(b)); // [1.5, 3, 0]

const minN = (arr, n = 1) => [...arr].sort((a, b) => a - b).slice(0, n);

minN([1, 2, 3]); // [1]
minN([1, 2, 3], 2); // [1,2]

const negate = func => (...args) => !func(...args);

[1, 2, 3, 4, 5, 6].filter(negate(n => n % 2 === 0)); // [ 1, 3, 5 ]

const randomIntArrayInRange = (min, max, n = 1) =>
  Array.from({ length: n }, () => Math.floor(Math.random() * (max - min + 1)) + min);
  
randomIntArrayInRange(12, 35, 10); // [ 34, 14, 27, 17, 30, 27, 20, 26, 21, 14 ]

const sample = arr => arr[Math.floor(Math.random() * arr.length)];

sample([3, 7, 9, 11]); // 9

const sampleSize = ([...arr], n = 1) => {
  let m = arr.length;
  while (m) {
    const i = Math.floor(Math.random() * m--);
    [arr[m], arr[i]] = [arr[i], arr[m]];
  }
  return arr.slice(0, n);
};

sampleSize([1, 2, 3], 2); // [3,1]
sampleSize([1, 2, 3], 4); // [2,3,1]

const shuffle = ([...arr]) => {
  let m = arr.length;
  while (m) {
    const i = Math.floor(Math.random() * m--);
    [arr[m], arr[i]] = [arr[i], arr[m]];
  }
  return arr;
};

const foo = [1, 2, 3];
shuffle(foo); // [2, 3, 1], foo = [1, 2, 3]

const nest = (items, id = null, link = 'parent_id') =>
  items
    .filter(item => item[link] === id)
    .map(item => ({ ...item, children: nest(items, item.id) }));

const comments = [
  { id: 1, parent_id: null },
  { id: 2, parent_id: 1 },
  { id: 3, parent_id: 1 },
  { id: 4, parent_id: 2 },
  { id: 5, parent_id: 4 }
];
const nestedComments = nest(comments); // [{ id: 1, parent_id: null, children: [...] }]

onst attempt = (fn, ...args) => {
  try {
    return fn(...args);
  } catch (e) {
    return e instanceof Error ? e : new Error(e);
  }
};
var elements = attempt(function(selector) {
  return document.querySelectorAll(selector);
}, '>_>');
if (elements instanceof Error) elements = []; // elements = []

const defer = (fn, ...args) => setTimeout(fn, 1, ...args);

defer(console.log, 'a'), console.log('b'); // logs 'b' then 'a'

const runPromisesInSeries = ps => ps.reduce((p, next) => p.then(next), Promise.resolve());
const delay = d => new Promise(r => setTimeout(r, d));

runPromisesInSeries([() => delay(1000), () => delay(2000)]);
//依次执行每个Promises ，总共需要3秒钟才能完成

const timeTaken = callback => {
  console.time('timeTaken');
  const r = callback();
  console.timeEnd('timeTaken');
  return r;
};

timeTaken(() => Math.pow(2, 10)); // 1024, (logged): timeTaken: 0.02099609375ms

const createEventHub = () => ({
  hub: Object.create(null),
  emit(event, data) {
    (this.hub[event] || []).forEach(handler => handler(data));
  },
  on(event, handler) {
    if (!this.hub[event]) this.hub[event] = [];
    this.hub[event].push(handler);
  },
  off(event, handler) {
    const i = (this.hub[event] || []).findIndex(h => h === handler);
    if (i > -1) this.hub[event].splice(i, 1);
    if (this.hub[event].length === 0) delete this.hub[event];
  }
});

const handler = data => console.log(data);
const hub = createEventHub();
let increment = 0;

// 订阅，监听不同事件
hub.on('message', handler);
hub.on('message', () => console.log('Message event fired'));
hub.on('increment', () => increment++);

// 发布：发出事件以调用所有订阅给它们的处理程序，并将数据作为参数传递给它们
hub.emit('message', 'hello world'); // 打印 'hello world' 和 'Message event fired'
hub.emit('message', { hello: 'world' }); // 打印 对象 和 'Message event fired'
hub.emit('increment'); // increment = 1

// 停止订阅
hub.off('message', handler);

const memoize = fn => {
  const cache = new Map();
  const cached = function(val) {
    return cache.has(val) ? cache.get(val) : cache.set(val, fn.call(this, val)) && cache.get(val);
  };
  cached.cache = cache;
  return cached;
};

/**
 * Create a cached version of a pure function.
 */
export function cached<F: Function> (fn: F): F {
  const cache = Object.create(null)
  return (function cachedFn (str: string) {
    const hit = cache[str]
    return hit || (cache[str] = fn(str))
  }: any)
}

const once = fn => {
  let called = false
  return function () {
    if (!called) {
      called = true
      fn.apply(this, arguments)
    }
  }
};

const flattenObject = (obj, prefix = '') =>
  Object.keys(obj).reduce((acc, k) => {
    const pre = prefix.length ? prefix + '.' : '';
    if (typeof obj[k] === 'object') Object.assign(acc, flattenObject(obj[k], pre + k));
    else acc[pre + k] = obj[k];
    return acc;
  }, {});
  
flattenObject({ a: { b: { c: 1 } }, d: 1 }); // { 'a.b.c': 1, d: 1 }

const unflattenObject = obj =>
  Object.keys(obj).reduce((acc, k) => {
    if (k.indexOf('.') !== -1) {
      const keys = k.split('.');
      Object.assign(
        acc,
        JSON.parse(
          '{' +
            keys.map((v, i) => (i !== keys.length - 1 ? `"${v}":{` : `"${v}":`)).join('') +
            obj[k] +
            '}'.repeat(keys.length)
        )
      );
    } else acc[k] = obj[k];
    return acc;
  }, {});
  
unflattenObject({ 'a.b.c': 1, d: 1 }); // { a: { b: { c: 1 } }, d: 1 }

const byteSize = str => new Blob([str]).size;

byteSize('😀'); // 4
byteSize('Hello World'); // 11

const capitalize = ([first, ...rest]) =>
  first.toUpperCase() + rest.join('');
  
capitalize('fooBar'); // 'FooBar'
capitalize('fooBar', true); // 'Foobar'

const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase());

capitalizeEveryWord('hello world!'); // 'Hello World!'

const decapitalize = ([first, ...rest]) =>
  first.toLowerCase() + rest.join('')

decapitalize('FooBar'); // 'fooBar'
decapitalize('FooBar'); // 'fooBar'

const luhnCheck = num => {
  let arr = (num + '')
    .split('')
    .reverse()
    .map(x => parseInt(x));
  let lastDigit = arr.splice(0, 1)[0];
  let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val * 2) % 9) || 9), 0);
  sum += lastDigit;
  return sum % 10 === 0;
};

luhnCheck('4485275742308327'); // true
luhnCheck(6011329933655299); //  false
luhnCheck(123456789); // false

const splitLines = str => str.split(/\r?\n/);

splitLines('This\nis a\nmultiline\nstring.\n'); // ['This', 'is a', 'multiline', 'string.' , '']

const stripHTMLTags = str => str.replace(/<[^>]*>/g, '');

stripHTMLTags('<p><em>lorem</em> <strong>ipsum</strong></p>'); // 'lorem ipsum'

const dayOfYear = date =>
  Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);

dayOfYear(new Date()); // 285

const forOwn = (obj, fn) => Object.keys(obj).forEach(key => fn(obj[key], key, obj));
forOwn({ foo: 'bar', a: 1 }, v => console.log(v)); // 'bar', 1

const getColonTimeFromDate = date => date.toTimeString().slice(0, 8);

getColonTimeFromDate(new Date()); // "08:38:00"

const getDaysDiffBetweenDates = (dateInitial, dateFinal) =>
  (dateFinal - dateInitial) / (1000 * 3600 * 24);
  
getDaysDiffBetweenDates(new Date('2019-01-01'), new Date('2019-10-14')); // 286

const is = (type, val) => ![, null].includes(val) && val.constructor === type;

is(Array, [1]); // true
is(ArrayBuffer, new ArrayBuffer()); // true
is(Map, new Map()); // true
is(RegExp, /./g); // true
is(Set, new Set()); // true
is(WeakMap, new WeakMap()); // true
is(WeakSet, new WeakSet()); // true
is(String, ''); // true
is(String, new String('')); // true
is(Number, 1); // true
is(Number, new Number(1)); // true
is(Boolean, true); // true
is(Boolean, new Boolean(true)); // true

const isAfterDate = (dateA, dateB) => dateA > dateB;

isAfterDate(new Date(2010, 10, 21), new Date(2010, 10, 20)); // true

const isBeforeDate = (dateA, dateB) => dateA < dateB;

isBeforeDate(new Date(2010, 10, 20), new Date(2010, 10, 21)); // true

const tomorrow = () => {
  let t = new Date();
  t.setDate(t.getDate() + 1);
  return t.toISOString().split('T')[0];
};

tomorrow(); // 2019-10-15 (如果明天是2019-10-15)

const equals = (a, b) => {
  if (a === b) return true;
  if (a instanceof Date && b instanceof Date) return a.getTime() === b.getTime();
  if (!a || !b || (typeof a !== 'object' && typeof b !== 'object')) return a === b;
  if (a.prototype !== b.prototype) return false;
  let keys = Object.keys(a);
  if (keys.length !== Object.keys(b).length) return false;
  return keys.every(k => equals(a[k], b[k]));
};

equals({ a: [2, { e: 3 }], b: [4], c: 'foo' }, { a: [2, { e: 3 }], b: [4], c: 'foo' }); // true

const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;

randomIntegerInRange(0, 5); // 3

const randomNumberInRange = (min, max) => Math.random() * (max - min) + min;

randomNumberInRange(2, 10); // 6.0211363285087005

const round = (n, decimals = 0) => Number(`${Math.round(`${n}e${decimals}`)}e-${decimals}`);

round(1.005, 2); // 1.01

const sum = (...arr) => [...arr].reduce((acc, val) => acc + val, 0);

sum(1, 2, 3, 4); // 10
sum(...[1, 2, 3, 4]); // 10

const toCurrency = (n, curr, LanguageFormat = undefined) =>
  Intl.NumberFormat(LanguageFormat, { style: 'currency', currency: curr }).format(n);
  
toCurrency(123456.789, 'EUR'); // €123,456.79
toCurrency(123456.789, 'USD', 'en-us'); // $123,456.79  
toCurrency(123456.789, 'USD', 'fa'); // ۱۲۳٬۴۵۶٫۷۹
toCurrency(322342436423.2435, 'JPY'); // ¥322,342,436,423 

const bottomVisible = () =>
  document.documentElement.clientHeight + window.scrollY >=
  (document.documentElement.scrollHeight || document.documentElement.clientHeight);

bottomVisible(); // true

const fs = require('fs');
const createDirIfNotExists = dir => (!fs.existsSync(dir) ? fs.mkdirSync(dir) : undefined);
createDirIfNotExists('test'); 

const currentURL = () => window.location.href;

currentURL(); // 'https://juejin.im'

const distance = (x0, y0, x1, y1) => Math.hypot(x1 - x0, y1 - y0);

distance(1, 1, 2, 3); // 2.23606797749979

const elementContains = (parent, child) => parent !== child && parent.contains(child);

elementContains(document.querySelector('head'), document.querySelector('title')); // true
elementContains(document.querySelector('body'), document.querySelector('body')); // false

const getStyle = (el, ruleName) => getComputedStyle(el)[ruleName];

getStyle(document.querySelector('p'), 'font-size'); // '16px'

const getType = v =>
  v === undefined ? 'undefined' : v === null ? 'null' : v.constructor.name.toLowerCase();
  
getType(new Set([1, 2, 3])); // 'set'
getType([1, 2, 3]); // 'array'

const hasClass = (el, className) => el.classList.contains(className);
hasClass(document.querySelector('p.special'), 'special'); // true

const hide = (...el) => [...el].forEach(e => (e.style.display = 'none'));

hide(document.querySelectorAll('img')); // 隐藏所有<img>标签

const httpsRedirect = () => {
  if (location.protocol !== 'https:') location.replace('https://' + location.href.split('//')[1]);
};

httpsRedirect(); // 若在`http://www.baidu.com`, 则跳转到`https://www.baidu.com`

const insertAfter = (el, htmlString) => el.insertAdjacentHTML('afterend', htmlString);

// <div id="myId">...</div> <p>after</p>
insertAfter(document.getElementById('myId'), '<p>after</p>'); 

const insertBefore = (el, htmlString) => el.insertAdjacentHTML('beforebegin', htmlString);

insertBefore(document.getElementById('myId'), '<p>before</p>'); // <p>before</p> <div id="myId">...</div>

const isBrowser = () => ![typeof window, typeof document].includes('undefined');

isBrowser(); // true (browser)
isBrowser(); // false (Node)

const isBrowserTabFocused = () => !document.hidden;

isBrowserTabFocused(); // true

const nodeListToArray = nodeList => [...nodeList];

nodeListToArray(document.childNodes); // [ <!DOCTYPE html>, html ]

const randomHexColorCode = () => {
  let n = (Math.random() * 0xfffff * 1000000).toString(16);
  return '#' + n.slice(0, 6);
};

randomHexColorCode(); // "#e34155"

const scrollToTop = () => {
  const c = document.documentElement.scrollTop || document.body.scrollTop;
  if (c > 0) {
    window.requestAnimationFrame(scrollToTop);
    window.scrollTo(0, c - c / 8);
  }
};

scrollToTop();

const smoothScroll = element =>
  document.querySelector(element).scrollIntoView({
    behavior: 'smooth'
  });
  
smoothScroll('#fooBar'); 
smoothScroll('.fooBar'); 

const detectDeviceType = () =>
  /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent)
    ? 'Mobile'
    : 'Desktop';

const getScrollPosition = (el = window) => ({
  x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft,
  y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop
});

getScrollPosition(); // {x: 0, y: 200}

const size = val =>
  Array.isArray(val)
    ? val.length
    : val && typeof val === 'object'
    ? val.size || val.length || Object.keys(val).length
    : typeof val === 'string'
    ? new Blob([val]).size
    : 0;

size([1, 2, 3, 4, 5]); // 5
size('size'); // 4
size({ one: 1, two: 2, three: 3 }); // 3

const escapeHTML = str =>
  str.replace(
    /[&<>'"]/g,
    tag =>
      ({
        '&': '&amp;',
        '<': '&lt;',
        '>': '&gt;',
        "'": '&#39;',
        '"': '&quot;'
      }[tag] || tag)
  );

escapeHTML('<a href="#">Me & you</a>'); // '&lt;a href=&quot;#&quot;&gt;Me &amp; you&lt;/a&gt;'

<script src="https://unpkg.com/[email protected]"></script>

npm install rough-viz

npm install react-roughviz
npm install vue-roughviz

pip install roughviz

import axios from 'axios'
import router from '../router'
import {MessageBox, Message} from 'element-ui'

let loginUrl = '/login'
// 根据环境切换接口地址
axios.defaults.baseURL = process.env.VUE_APP_API
axios.defaults.headers = {'X-Requested-With': 'XMLHttpRequest'}
axios.defaults.timeout = 60000

// 请求拦截器
axios.interceptors.request.use(
  config => {
    if (router.history.current.path !== loginUrl) {
      let token = window.sessionStorage.getItem('token')
      if (token == null) {
        router.replace({path: loginUrl, query: {redirect: router.currentRoute.fullPath}})
        return false
      } else {
        config.headers['Authorization'] = 'JWT ' + token
      }
    }
    return config
  }, error => {
    Message.warning(error)
    return Promise.reject(error)
  })

axios.interceptors.response.use(
  response => {
    return response.data
  }, error => {
    if (error.response !== undefined) {
      switch (error.response.status) {
        case 400:
          MessageBox.alert(error.response.data)
          break
        case 401:
          if (window.sessionStorage.getItem('out') === null) {
            window.sessionStorage.setItem('out', 1)
            MessageBox.confirm('会话已失效! 请重新登录', '提示', {confirmButtonText: '重新登录', cancelButtonText: '取消', type: 'warning'}).then(() => {
              router.replace({path: loginUrl, query: {redirect: router.currentRoute.fullPath}})
            }).catch(action => {
              window.sessionStorage.clear()
              window.localStorage.clear()
            })
          }
          break
        case 402:
          MessageBox.confirm('登陆超时 ！', '提示', {confirmButtonText: '重新登录', cancelButtonText: '取消', type: 'warning'}).then(() => {
            router.replace({path: loginUrl, query: {redirect: router.currentRoute.fullPath}})
          })
          break
        case 403:
          MessageBox.alert('没有权限！')
          break
        // ...忽略
        default:
          MessageBox.alert(`连接错误${error.response.status}`)
    }
    return Promise.resolve(error.response)
  }
  return Promise.resolve(error)
})

export default {
  get (url, param) {
    if (param !== undefined) {
      Object.assign(param, {_t: (new Date()).getTime()})
    } else {
      param = {_t: (new Date()).getTime()}
    }
    return axios({method: 'get', url, params: param})
  },
  // 不常更新的数据用这个
  getData (url, param) {
    return axios({method: 'get', url, params: param})
  },
  post (url, param, config) {
    return axios.post(url, param, config)
  },
  put: axios.put,
  _delete: axios.delete
}

import http from '@/utils/request'
export default {
  A (param) { return http.get('/api/', param) },
  B (param) { return http.post('/api/', param) }
  C (param) { return http.put('/api/', param) },
  D (param) { return http._delete('/api/', {data: param}) },
}

import http from '@/utils/request'
import account from './account'
// 忽略...
const api = Object.assign({}, http, account, \*...其它模块*\)
export default api

import Vue from 'vue'
import api from './api/index'
// 略...

const errorHandler = (error, vm) => {
  console.error(vm)
  console.error(error)
}

Vue.config.errorHandler = errorHandler
export default {
  install (Vue) {
    // 添加组件
    // 添加过滤器
    })
    // 全局报错处理
    Vue.prototype.$throw = (error) => errorHandler(error, this)
    Vue.prototype.$http = api
    // 其它配置
  }
}

async getData () {
    const params = {/*...key : value...*/}
    let res = await this.$http.A(params)
    res.code === 4000 ? (this.aSata = res.data) : this.$message.warning(res.msg)
}

<template>
    <BaseInput  v-model="searchText"  @keydown.enter="search"/>
    <BaseButton @click="search">
        <BaseIcon name="search"/>
    </BaseButton>
</template>
<script>
    import BaseButton from './baseButton'
    import BaseIcon from './baseIcon'
    import BaseInput from './baseInput'
    export default {
      components: { BaseButton, BaseIcon, BaseInput }
    }
</script>

import Vue from 'vue'
/**
 * 首字母大写
 * @param str 字符串
 * @example heheHaha
 * @return {string} HeheHaha
 */
function capitalizeFirstLetter (str) {
  return str.charAt(0).toUpperCase() + str.slice(1)
}
/**
 * 对符合'xx/xx.vue'组件格式的组件取组件名
 * @param str fileName
 * @example abc/bcd/def/basicTable.vue
 * @return {string} BasicTable
 */
function validateFileName (str) {
  return /^\S+\.vue$/.test(str) &&
    str.replace(/^\S+\/(\w+)\.vue$/, (rs, $1) => capitalizeFirstLetter($1))
}
const requireComponent = require.context('./', true, /\.vue$/)
// 找到组件文件夹下以.vue命名的文件，如果文件名为index，那么取组件中的name作为注册的组件名
requireComponent.keys().forEach(filePath => {
  const componentConfig = requireComponent(filePath)
  const fileName = validateFileName(filePath)
  const componentName = fileName.toLowerCase() === 'index'
    ? capitalizeFirstLetter(componentConfig.default.name)
    : fileName
  Vue.component(componentName, componentConfig.default || componentConfig)
})

sudo npm install hiper -g
# 或者使用 yarn:
# sudo yarn global add hiper

export default {
  name: 'keep-alive',
  abstract: true,
  ...
}

import { xxx } from 'xxx'
const A = () => {
    .....
}

export default {
    name: 'xxx',
    abstract: true,
    props: ['...', '...'],
    // 生命周期钩子函数
    created () {
      ....
    },
    ....
    destroyed () {
      ....
    },
    render() {
        const vnode = this.$slots.default
        ....
        return vnode
    },
})

const throttle = function(fn, wait=50, isDebounce, ctx) {
  let timer
  let lastCall = 0
  return function (...params) {
    if (isDebounce) {
      if (timer) clearTimeout(timer)
      timer = setTimeout(() => {
        fn.apply(ctx, params)
      }, wait)
    } else {
      const now = new Date().getTime()
      if (now - lastCall < wait) return
      lastCall = now
      fn.apply(ctx, params)
    }
  }
}

export default {
    name: 'Throttle',
    abstract: true,
    props: {
      time: Number,
      events: String,
      isDebounce: {
        type: Boolean,
        default: false
      },
    },
    created () {
      this.eventKeys = this.events.split(',')
      this.originMap = {}
      this.throttledMap = {}
    },
    render() {
        const vnode = this.$slots.default[0]
        this.eventKeys.forEach((key) => {
            const target = vnode.data.on[key]
            if (target === this.originMap[key] && this.throttledMap[key]) {
                vnode.data.on[key] = this.throttledMap[key]
            } else if (target) {
                this.originMap[key] = target
                this.throttledMap[key] = throttle(target, this.time, this.isDebounce, vnode)
                vnode.data.on[key] = this.throttledMap[key]
            }
        })
        return vnode
    },
})

import Throttle from '../Throttle'
....
Vue.component('Throttle', Throttle)

<div id="app">
    <Throttle :time="1000" events="click">
        <button @click="onClick($event, 1)">click+1 {{val}}</button>
    </Throttle>
    <Throttle :time="1000" events="click" :isDebounce="true">
        <button @click="onAdd">click+3 {{val}}</button>
    </Throttle>
    <Throttle :time="3300" events="mouseleave" :isDebounce="true">
        <button @mouseleave.prevent="onAdd">click+3 {{val}}</button>
    </Throttle>
</div>

const app = new Vue({
    el: '#app',
    data () {
        return {
            val: 0
        }
    },
    methods: {
        onClick ($ev, val) {
            this.val += val
        },
        onAdd () {
            this.val += 3
        }
    }
})

import Vue from 'Vue'
export default new Vue

beforeDestroy(){
    bus.$off('click')
 }

 Vue.prototype._init = function (options?: Object) {
    const vm: Component = this
    // a uid vm实例唯一标识
    vm._uid = uid++
    // ....
    }

class EventBus {
  constructor (vue) {
    if (!this.handles) {
      Object.defineProperty(this, 'handles', {
        value: {},
        enumerable: false
      })
    }
    this.Vue = vue
    // _uid和EventName的映射
    this.eventMapUid = {}
  }
  setEventMapUid (uid, eventName) {
    if (!this.eventMapUid[uid]) this.eventMapUid[uid] = []
    this.eventMapUid[uid].push(eventName) // 把每个_uid订阅的事件名字push到各自uid所属的数组里
  }
  $on (eventName, callback, vm) {
    // vm是在组件内部使用时组件当前的this用于取_uid
    if (!this.handles[eventName]) this.handles[eventName] = []
    this.handles[eventName].push(callback)
    if (vm instanceof this.Vue) this.setEventMapUid(vm._uid, eventName)
  }
  $emit () {
    let args = [...arguments]
    let eventName = args[0]
    let params = args.slice(1)
    if (this.handles[eventName]) {
      let len = this.handles[eventName].length
      for (let i = 0; i < len; i++) {
        this.handles[eventName][i](...params)
      }
    }
  }
  $offVmEvent (uid) {
    let currentEvents = this.eventMapUid[uid] || []
    currentEvents.forEach(event => {
      this.$off(event)
    })
  }
  $off (eventName) {
    delete this.handles[eventName]
  }
}
// 写成Vue插件形式，直接引入然后Vue.use($EventBus)进行使用
let $EventBus = {}

$EventBus.install = (Vue, option) => {
  Vue.prototype.$eventBus = new EventBus(Vue)
  Vue.mixin({
    beforeDestroy () {
      // 拦截beforeDestroy钩子自动销毁自身所有订阅的事件
      this.$eventBus.$offVmEvent(this._uid) 
    }
  })
}

export default $EventBus

// main.js中
...
import EventBus from './eventBus.js'
Vue.use(EnemtBus)
...

 created () {
    let text = Array(1000000).fill('xxx').join(',')
    this.$eventBus.$on('home-on', (...args) => {
      console.log('home $on====>>>', ...args)
      this.text = text
    }, this) // 注意第三个参数需要传当前组件的this，如果不传则需要手动销毁
  },
  mounted () {
    setTimeout(() => {
      this.$eventBus.$emit('home-on', '这是home $emit参数', 'ee')
    }, 1000)
  },
  beforeDestroy () {
    // 这里就不需要手动的off销毁eventBus订阅的事件了
  }

const TerserPlugin = require('terser-webpack-plugin')
....
new TerserPlugin({
cache: true,
parallel: true,
sourceMap: true, // Must be set to true if using source-maps in production
terserOptions: {
  compress: {
    drop_console: true,
    drop_debugger: true
  }
}
})

const CompressionWebpackPlugin = require（'compression-webpack-plugin'）
module.exports = { 
    “plugins”：[new CompressionWebpackPlugin] 
}

const CompressionWebpackPlugin = require('compression-webpack-plugin');

webpackConfig.plugins.push(
    new CompressionWebpackPlugin({
      asset: '[path].gz[query]',
      algorithm: 'gzip',
      test: new RegExp('\\.(js|css)$'),
      // 只处理大于xx字节 的文件，默认：0
      threshold: 10240,
      // 示例：一个1024b大小的文件，压缩后大小为768b，minRatio : 0.75
      minRatio: 0.8 // 默认: 0.8
      // 是否删除源文件，默认: false
      deleteOriginalAssets: false
    })
)

server {
    gzip on;
    gzip_static on;    
    gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;
    gzip_proxied  any;
    gzip_vary on;
    gzip_comp_level 6;
    gzip_buffers 16 8k;
    gzip_http_version 1.1;    
    ...
}

$ sudo service nginx restart

// Javascript/Typescript 非严格模式
function extractIds (list) {
  return list.map(member => member.id)
}

// Typescript 严格模式
function extractIds (list) {
  //              ❌ ^^^^
  //                 Parameter 'list' implicitly
  //                 has an 'any' type. ts(7006)
  return list.map(member => member.id)
  //           ❌ ^^^^^^
  //              Parameter 'member' implicitly
  //              has an 'any' type. ts(7006)
}

// Typescript 严格模式
interface Member {
  id: number
  name: string
}

function extractIds (list: Member[]) {
  return list.map(member => member.id)
}

// Typescript 严格模式
function onChangeCheckbox (e) {
  //                    ❌ ^
  //                       Parameter 'e' implicitly
  //                       has an 'any' type. ts(7006)
  e.preventDefault()
  const value = e.target.checked
  validateCheckbox(value)
}

// Typescript 严格模式
interface ChangeCheckboxEvent extends MouseEvent {
  target: HTMLInputElement
}

function onChangeCheckbox (e: ChangeCheckboxEvent) {
  e.preventDefault()
  const value = e.target.checked
  validateCheckbox(value)
}

// Typescript 严格模式
import { Vector } from 'sylvester'
//                  ❌ ^^^^^^^^^^^
//                     Could not find a declaration file 
//                     for module 'sylvester'.
//                     'sylvester' implicitly has an 'any' type. 
//                     Try `npm install @types/sylvester` 
//                     if it exists or add a new declaration (.d.ts)
//                     file containing `declare module 'sylvester';`
//                     ts(7016)

// Javascript/Typescript 非严格模式
function uppercaseLabel () {
  return this.label.toUpperCase()
}

const config = {
  label: 'foo-config',
  uppercaseLabel
}

config.uppercaseLabel()
// FOO-CONFIG

// Typescript严格模式
function uppercaseLabel () {
  return this.label.toUpperCase()
  //  ❌ ^^^^
  //     'this' implicitly has type 'any' 
  //     because it does not have a type annotation. ts(2683)
}

// Typescript strict mode
const config = {
  label: 'foo-config',
  uppercaseLabel () {
    return this.label.toUpperCase()
  }
}

// Typescript strict mode
interface MyConfig {
  label: string
  uppercaseLabel: (params: void) => string
}

const config: MyConfig = {
  label: 'foo-config',
  uppercaseLabel () {
    return this.label.toUpperCase()
  }
}

// Typescript 非严格模式
function getArticleById (articles: Article[], id: string) {
  const article = articles.find(article => article.id === id)
  return article.meta
}

// Typescript strict mode
function getArticleById (articles: Article[], id: string) {
  const article = articles.find(article => article.id === id)
  return article.meta
  //  ❌ ^^^^^^^
  //     Object is possibly 'undefined'. ts(2532)
}

// Typescript strict mode
function getArticleById (articles: Article[], id: string) {
  const article = articles.find(article => article.id === id)
  if (typeof article === 'undefined') {
    throw new Error(`Could not find an article with id: ${id}.`)
  }

  return article.meta
}

// Typescript non-strict mode
class User {
  username: string;
}

const user = new User();

const username = user.username.toLowerCase();

class User {
  username: string;
  //    ❌  ^^^^^^
  //     Property 'username' has no initializer
  //     and is not definitely assigned in the constructor
}

const user = new User();
/
const username = user.username.toLowerCase();
 //                 ❌         ^^^^^^^^^^^^
//          TypeError: Cannot read property 'toLowerCase' of undefined

class User {
  username: string | undefined;
}

const user = new User();

const username = typeof user.username === "string"
  ? user.username.toLowerCase()
  : "n/a";

class User {
  username = "n/a";
}

const user = new User();

// OK
const username = user.username.toLowerCase();

class User {
  username: string;

  constructor(username: string) {
    this.username = username;
  }
}

const user = new User("mariusschulz");

// OK
const username = user.username.toLowerCase();

class User {
  constructor(public username: string) {}
}

const user = new User("mariusschulz");

// OK
const username = user.username.toLowerCase();

class User {
  username!: string;

  constructor(username: string) {
    this.initialize(username);
  }

  private initialize(username: string) {
    this.username = username;
  }
}

const user = new User("mariusschulz");

// OK
const username = user.username.toLowerCase();

// JavaScript
function sum (num1: number, num2: number) {
  return num1 + num2
}

sum.apply(null, [1, 2])
// 3

// Typescript non-strict mode
function sum (num1: number, num2: number) {
  return num1 + num2
}

sum.apply(null, [1, 2, 3])
// 还是...3?

// Typescript strict mode
function sum (num1: number, num2: number) {
  return num1 + num2
}

sum.apply(null, [1, 2, 3])
//           ❌ ^^^^^^^^^
//              Argument of type '[number, number, number]' is not 
//              assignable to parameter of type '[number, number]'.
//                Types of property 'length' are incompatible.
//                  Type '3' is not assignable to type '2'. ts(2345)

// Typescript strict mode
function sum (...args: number[]) {
  return args.reduce<number>((total, num) => total + num, 0)
}

sum.apply(null, [1, 2, 3])
// 6

declare let f1: (x: Animal) => void;
declare let f2: (x: Dog) => void;
declare let f3: (x: Cat) => void;
f1 = f2;  // 启用 --strictFunctionTypes 时错误
f2 = f1;  // 正确
f2 = f3;  // 错误

interface Comparer<T> {
    compare: (a: T, b: T) => number;
}

declare let animalComparer: Comparer<Animal>;
declare let dogComparer: Comparer<Dog>;

animalComparer = dogComparer;  // 错误
dogComparer = animalComparer;  // 正确

const getRandomColor = () => {
  const letters = '0123456789ABCDEF';
  let color = '#';
  for (let i = 0; i < 6; i++) {
    color += letters[Math.floor(Math.random() * 16)]
  }
  return color;
};

const translateY = (value) => {
  return `translateY(${value}px)`;
}

const DynamicBarChart = (props) =>  {
  const [dataQueue, setDataQueue] = useState([]);
  const [activeItemIdx, setActiveItemIdx] = useState(0);
  const [highestValue, setHighestValue] = useState(0);
  const [currentValues, setCurrentValues] = useState({});
  const [firstRun, setFirstRun] = useState(false);
  // 其它代码...
  }

const [属性, 操作属性的方法] = useState(默认值);

// 动态跑起来～
function start () {
  if (activeItemIdx > 1) {
    return;
  }
  nextStep(true);
}
// 对下一帧数据进行处理
function setNextValues () {
  // 没有帧数时（即已结束），停止渲染
  if (!dataQueue[activeItemIdx]) {
    iterationTimeoutHolder = null;
    return;
  }
  //  每一帧的数据数组
  const roundData = dataQueue[activeItemIdx].values;
  const nextValues = {};
  let highestValue = 0;
  //  处理数据，用作最后渲染（各种样式，颜色）
  roundData.map((c) => {
    nextValues[c.id] = {
      ...c,
      color: c.color || (currentValues[c.id] || {}).color || getRandomColor()
    };

    if (Math.abs(c.value) > highestValue) {
      highestValue = Math.abs(c.value);
    }

    return c;
  });

  // 属性的操作，触发useEffect
  setCurrentValues(nextValues);
  setHighestValue(highestValue);
  setActiveItemIdx(activeItemIdx + 1);
}
// 触发下一步，循环
function nextStep (firstRun = false) {
  setFirstRun(firstRun);
  setNextValues();
}

// 取原始数据
useEffect(() => {
  setDataQueue(props.data);
}, []);
// 触发动态
useEffect(() => {
  start();
}, [dataQueue]);
// 设触发动态间隔
useEffect(() => {
  iterationTimeoutHolder = window.setTimeout(nextStep, 1000);
  return () => {
    if (iterationTimeoutHolder) {
      window.clearTimeout(iterationTimeoutHolder);
    }
  };
}, [activeItemIdx]);

useEffect(() => {
  document.title = `You clicked ${count} times`;
}, [count]); // 仅在 count 更改时更新

const keys = Object.keys(currentValues);
const { barGapSize, barHeight, showTitle } = props;
const maxValue = highestValue / 0.85;
const sortedCurrentValues = keys.sort((a, b) => currentValues[b].value - currentValues[a].value);
const currentItem = dataQueue[activeItemIdx - 1] || {};

<div className="live-chart">
{
<React.Fragment>
  {
    showTitle &&
    <h1>{currentItem.name}</h1>
  }
  <section className="chart">
    <div className="chart-bars" style={{ height: (barHeight + barGapSize) * keys.length }}>
      {
        sortedCurrentValues.map((key, idx) => {
          const currentValueData = currentValues[key];
          const value = currentValueData.value
          let width = Math.abs((value / maxValue * 100));
          let widthStr;
          if (isNaN(width) || !width) {
            widthStr = '1px';
          } else {
            widthStr = `${width}%`;
          }

          return (
            <div className={`bar-wrapper`} style={{ transform: translateY((barHeight + barGapSize) * idx), transitionDuration: 200 / 1000 }} key={`bar_${key}`}>
              <label>
                {
                  !currentValueData.label
                    ? key
                    : currentValueData.label
                }
              </label>
              <div className="bar" style={{ height: barHeight, width: widthStr, background: typeof currentValueData.color === 'string' ? currentValueData.color : `linear-gradient(to right, ${currentValueData.color.join(',')})` }} />
              <span className="value" style={{ color: typeof currentValueData.color === 'string' ? currentValueData.color : currentValueData.color[0] }}>{currentValueData.value}</span>
            </div>
          );
        })
      }
    </div>
  </section>
</React.Fragment>
}
</div>

DynamicBarChart.propTypes = {
  showTitle: PropTypes.bool,
  iterationTimeout: PropTypes.number,
  data: PropTypes.array,
  startRunningTimeout: PropTypes.number,
  barHeight: PropTypes.number,
  barGapSize: PropTypes.number,
  baseline: PropTypes.number,
};

DynamicBarChart.defaultProps = {
  showTitle: true,
  iterationTimeout: 200,
  data: [],
  startRunningTimeout: 0,
  barHeight: 50,
  barGapSize: 20,
  baseline: null,
};

export {
  DynamicBarChart
};

import React, { Component } from "react";

import { DynamicBarChart } from "./DynamicBarChart";

import helpers from "./helpers";
import mocks from "./mocks";

import "react-dynamic-charts/dist/index.css";

export default class App extends Component {
  render() {
    return (
      <DynamicBarChart
            barGapSize={10}
            data={helpers.generateData(100, mocks.defaultChart, {
              prefix: "Iteration"
            })}
            iterationTimeout={100}
            showTitle={true}
            startRunningTimeout={2500}
          />
      )
  }
}

function getRandomNumber(min, max) {
  return Math.floor(Math.random() * (max - min + 1) + min);
};

function generateData(iterations = 100, defaultValues = [], namePrefix = {}, maxJump = 100) {
  const arr = [];
  for (let i = 0; i <= iterations; i++) {
    const values = defaultValues.map((v, idx) => {
      if (i === 0 && typeof v.value === 'number') {
        return v;
      }
      return {
        ...v,
        value: i === 0 ? this.getRandomNumber(1, 1000) : arr[i - 1].values[idx].value + this.getRandomNumber(0, maxJump)
      }
    });
    arr.push({
      name: `${namePrefix.prefix || ''} ${(namePrefix.initialValue || 0) + i}`,
      values
    });
  }
  return arr;
};

export default {
  getRandomNumber,
  generateData
}

import helpers from './helpers';
const defaultChart = [
  {
    id: 1,
    label: 'Google',
    value: helpers.getRandomNumber(0, 50)
  },
  {
    id: 2,
    label: 'Facebook',
    value: helpers.getRandomNumber(0, 50)
  },
  {
    id: 3,
    label: 'Outbrain',
    value: helpers.getRandomNumber(0, 50)
  },
  {
    id: 4,
    label: 'Apple',
    value: helpers.getRandomNumber(0, 50)
  },
  {
    id: 5,
    label: 'Amazon',
    value: helpers.getRandomNumber(0, 50)
  },
];
export default {
  defaultChart,
}

import React, { useState, useEffect } from 'react';
import PropTypes from 'prop-types';
import './styles.scss';

const getRandomColor = () => {
  const letters = '0123456789ABCDEF';
  let color = '#';
  for (let i = 0; i < 6; i++) {
    color += letters[Math.floor(Math.random() * 16)]
  }
  return color;
};

const translateY = (value) => {
  return `translateY(${value}px)`;
}

const DynamicBarChart = (props) => {
  const [dataQueue, setDataQueue] = useState([]);
  const [activeItemIdx, setActiveItemIdx] = useState(0);
  const [highestValue, setHighestValue] = useState(0);
  const [currentValues, setCurrentValues] = useState({});
  const [firstRun, setFirstRun] = useState(false);
  let iterationTimeoutHolder = null;

  function start () {
    if (activeItemIdx > 1) {
      return;
    }
    nextStep(true);
  }

  function setNextValues () {
    if (!dataQueue[activeItemIdx]) {
      iterationTimeoutHolder = null;
      return;
    }
    
    const roundData = dataQueue[activeItemIdx].values;
    const nextValues = {};
    let highestValue = 0;
    roundData.map((c) => {
      nextValues[c.id] = {
        ...c,
        color: c.color || (currentValues[c.id] || {}).color || getRandomColor()
      };

      if (Math.abs(c.value) > highestValue) {
        highestValue = Math.abs(c.value);
      }

      return c;
    });
    console.table(highestValue);

    setCurrentValues(nextValues);
    setHighestValue(highestValue);
    setActiveItemIdx(activeItemIdx + 1);
  }

  function nextStep (firstRun = false) {
    setFirstRun(firstRun);
    setNextValues();
  }

  useEffect(() => {
    setDataQueue(props.data);
  }, []);

  useEffect(() => {
    start();
  }, [dataQueue]);

  useEffect(() => {
    iterationTimeoutHolder = window.setTimeout(nextStep, 1000);
    return () => {
      if (iterationTimeoutHolder) {
        window.clearTimeout(iterationTimeoutHolder);
      }
    };
  }, [activeItemIdx]);

  const keys = Object.keys(currentValues);
  const { barGapSize, barHeight, showTitle, data } = props;
  console.table('data', data);
  const maxValue = highestValue / 0.85;
  const sortedCurrentValues = keys.sort((a, b) => currentValues[b].value - currentValues[a].value);
  const currentItem = dataQueue[activeItemIdx - 1] || {};

  return (
    <div className="live-chart">
      {
        <React.Fragment>
          {
            showTitle &&
            <h1>{currentItem.name}</h1>
          }
          <section className="chart">
            <div className="chart-bars" style={{ height: (barHeight + barGapSize) * keys.length }}>
              {
                sortedCurrentValues.map((key, idx) => {
                  const currentValueData = currentValues[key];
                  const value = currentValueData.value
                  let width = Math.abs((value / maxValue * 100));
                  let widthStr;
                  if (isNaN(width) || !width) {
                    widthStr = '1px';
                  } else {
                    widthStr = `${width}%`;
                  }

                  return (
                    <div className={`bar-wrapper`} style={{ transform: translateY((barHeight + barGapSize) * idx), transitionDuration: 200 / 1000 }} key={`bar_${key}`}>
                      <label>
                        {
                          !currentValueData.label
                            ? key
                            : currentValueData.label
                        }
                      </label>
                      <div className="bar" style={{ height: barHeight, width: widthStr, background: typeof currentValueData.color === 'string' ? currentValueData.color : `linear-gradient(to right, ${currentValueData.color.join(',')})` }} />
                      <span className="value" style={{ color: typeof currentValueData.color === 'string' ? currentValueData.color : currentValueData.color[0] }}>{currentValueData.value}</span>
                    </div>
                  );
                })
              }
            </div>
          </section>
        </React.Fragment>
      }
    </div>
  );
};

DynamicBarChart.propTypes = {
  showTitle: PropTypes.bool,
  iterationTimeout: PropTypes.number,
  data: PropTypes.array,
  startRunningTimeout: PropTypes.number,
  barHeight: PropTypes.number,
  barGapSize: PropTypes.number,
  baseline: PropTypes.number,
};

DynamicBarChart.defaultProps = {
  showTitle: true,
  iterationTimeout: 200,
  data: [],
  startRunningTimeout: 0,
  barHeight: 50,
  barGapSize: 20,
  baseline: null,
};

export {
  DynamicBarChart
};

.live-chart {
  width: 100%;
  padding: 20px;
  box-sizing: border-box;
  position: relative;
  text-align: center;
  h1 {
    font-weight: 700;
    font-size: 60px;
    text-transform: uppercase;
    text-align: center;
    padding: 20px 10px;
    margin: 0;
  }

  .chart {
    position: relative;
    margin: 20px auto;
  }

  .chart-bars {
    position: relative;
    width: 100%;
  }
  
  .bar-wrapper {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    position: absolute;
    top: 0;
    left: 0;
    transform: translateY(0);
    transition: transform 0.5s linear;
    padding-left: 200px;
    box-sizing: border-box;
    width: 100%;
    justify-content: flex-start;

    label {
      position: absolute;
      height: 100%;
      width: 200px;
      left: 0;
      padding: 0 10px;
      box-sizing: border-box;
      text-align: right;
      top: 50%;
      transform: translateY(-50%);
      font-size: 16px;
      font-weight: 700;
      display: flex;
      justify-content: flex-end;
      align-items: center;
    }

    .value {
      font-size: 16px;
      font-weight: 700;
      margin-left: 10px;
    }

    .bar {
      width: 0%;
      transition: width 0.5s linear;
    }
  }
}

function fetchData() {
  fetch(path).then(res => doSomeThing(res.data));
}

window.addEventListener('scroll', fetchData);

const box = document.querySelector('.box');
const intersectionObserver = new IntersectionObserver((entries) => {
  entries.forEach((item) => {
    if (item.isIntersecting) {
      console.log('进入可视区域');
    }
  })
});
intersectionObserver.observe(box);

const io = new IntersectionObserver((entries) => {
  console.log(entries);
}, {
  threshold: [0, 0.5],
  root: document.querySelector('.container'),
  rootMargin: "10px 10px 30px 20px",
});

observer.observer（nodeone）; //仅观察nodeOne 
observer.observer（nodeTwo）; //观察nodeOne和nodeTwo 
observer.unobserve（nodeOne）; //停止观察nodeOne
observer.disconnect（）; //没有观察任何节点

class SlidingWindowScroll extends React.Component {
this.$bottomElement = React.createRef();
...
componentDidMount() {
    this.intiateScrollObserver();
}
intiateScrollObserver = () => {
    const options = {
      root: null,
      rootMargin: '0px',
      threshold: 0.1
    };
    this.observer = new IntersectionObserver(this.callback, options);
    this.observer.observe(this.$bottomElement.current);
}
render() {
    return (
    <li className='img' ref={this.$bottomElement}>
    )
}

const THRESHOLD = 15;
const SlidingWindowScrollHook = (props) =>  {
  const [start, setStart] = useState(0);
  const [end, setEnd] = useState(THRESHOLD);
  const [observer, setObserver] = useState(null);
  // 其它代码...
}

const [属性, 操作属性的方法] = useState(默认值);

const $bottomElement = useRef();
const $topElement = useRef();

useEffect(() => {
    // 定义观察
    intiateScrollObserver();
    return () => {
      // 放弃观察
      resetObservation()
  }
},[end])

// 定义观察
const intiateScrollObserver = () => {
    const options = {
      root: null,
      rootMargin: '0px',
      threshold: 0.1
    };
    const Observer = new IntersectionObserver(callback, options)
    // 分别观察开头和结尾的元素
    if ($topElement.current) {
      Observer.observe($topElement.current);
    }
    if ($bottomElement.current) {
      Observer.observe($bottomElement.current);
    }
    // 设初始值
    setObserver(Observer)    
}

// 交叉观察的具体回调，观察每个节点，并对实时头尾元素索引处理
const callback = (entries, observer) => {
    entries.forEach((entry, index) => {
      const listLength = props.list.length;
      // 向下滚动，刷新数据
      if (entry.isIntersecting && entry.target.id === "bottom") {
        const maxStartIndex = listLength - 1 - THRESHOLD;     // 当前头部的索引
        const maxEndIndex = listLength - 1;                   // 当前尾部的索引
        const newEnd = (end + 10) <= maxEndIndex ? end + 10 : maxEndIndex; // 下一轮增加尾部
        const newStart = (end - 5) <= maxStartIndex ? end - 5 : maxStartIndex; // 在上一轮的基础上计算头部
        setStart(newStart)
        setEnd(newEnd)
      }
      // 向上滚动，刷新数据
      if (entry.isIntersecting && entry.target.id === "top") {
        const newEnd = end === THRESHOLD ? THRESHOLD : (end - 10 > THRESHOLD ? end - 10 : THRESHOLD); // 向上滚动尾部元素索引不得小于15
        let newStart = start === 0 ? 0 : (start - 10 > 0 ? start - 10 : 0); // 头部元素索引最小值为0
        setStart(newStart)
        setEnd(newEnd)
        }
    });
}

// 停止滚动时放弃观察
const resetObservation = () => {
    observer && observer.unobserve($bottomElement.current); 
    observer && observer.unobserve($topElement.current);
}

// 渲染时，头尾ref处理
const getReference = (index, isLastIndex) => {
    if (index === 0)
      return $topElement;
    if (isLastIndex) 
      return $bottomElement;
    return null;
}

  const {list, height} = props; // 数据，节点高度
  const updatedList = list.slice(start, end); // 数据切割
  
  const lastIndex = updatedList.length - 1;
  return (
    <ul style={{position: 'relative'}}>
      {updatedList.map((item, index) => {
        const top = (height * (index + start)) + 'px'; // 基于相对 & 绝对定位 计算
        const refVal = getReference(index, index === lastIndex); // map循环中赋予头尾ref
        const id = index === 0 ? 'top' : (index === lastIndex ? 'bottom' : ''); // 绑ID
        return (<li className="li-card" key={item.key} style={{top}} ref={refVal} id={id}>{item.value}</li>);
      })}
    </ul>
  );

import React from 'react';
import './App.css';
import { SlidingWindowScrollHook } from "./SlidingWindowScrollHook";
import MY_ENDLESS_LIST from './Constants';

function App() {
  return (
    <div className="App">
     <h1>15个元素实现无限滚动</h1>
      <SlidingWindowScrollHook list={MY_ENDLESS_LIST} height={195}/>
    </div>
  );
}

export default App;

const MY_ENDLESS_LIST = [
  {
    key: 1,
    value: 'A'
  },
  {
    key: 2,
    value: 'B'
  },
  {
    key: 3,
    value: 'C'
  },
  // 中间就不贴了...
  {
    key: 45,
    value: 'AS'
  }
]

import React, { useState, useEffect, useRef } from "react";
const THRESHOLD = 15;

const SlidingWindowScrollHook = (props) =>  {
  const [start, setStart] = useState(0);
  const [end, setEnd] = useState(THRESHOLD);
  const [observer, setObserver] = useState(null);
  const $bottomElement = useRef();
  const $topElement = useRef();

  useEffect(() => {
    intiateScrollObserver();
    return () => {
      resetObservation()
  }
  // eslint-disable-next-line react-hooks/exhaustive-deps
  },[start, end])

  const intiateScrollObserver = () => {
    const options = {
      root: null,
      rootMargin: '0px',
      threshold: 0.1
    };
    const Observer = new IntersectionObserver(callback, options)
    if ($topElement.current) {
      Observer.observe($topElement.current);
    }
    if ($bottomElement.current) {
      Observer.observe($bottomElement.current);
    }
    setObserver(Observer)    
  }

  const callback = (entries, observer) => {
    entries.forEach((entry, index) => {
      const listLength = props.list.length;
      // Scroll Down
      if (entry.isIntersecting && entry.target.id === "bottom") {
        const maxStartIndex = listLength - 1 - THRESHOLD;     // Maximum index value `start` can take
        const maxEndIndex = listLength - 1;                   // Maximum index value `end` can take
        const newEnd = (end + 10) <= maxEndIndex ? end + 10 : maxEndIndex;
        const newStart = (end - 5) <= maxStartIndex ? end - 5 : maxStartIndex;
        setStart(newStart)
        setEnd(newEnd)
      }
      // Scroll up
      if (entry.isIntersecting && entry.target.id === "top") {
        const newEnd = end === THRESHOLD ? THRESHOLD : (end - 10 > THRESHOLD ? end - 10 : THRESHOLD);
        let newStart = start === 0 ? 0 : (start - 10 > 0 ? start - 10 : 0);
        setStart(newStart)
        setEnd(newEnd)
      }
      
    });
  }
  const resetObservation = () => {
    observer && observer.unobserve($bottomElement.current);
    observer && observer.unobserve($topElement.current);
  }


  const getReference = (index, isLastIndex) => {
    if (index === 0)
      return $topElement;
    if (isLastIndex) 
      return $bottomElement;
    return null;
  }

  const {list, height} = props;
  const updatedList = list.slice(start, end);
  const lastIndex = updatedList.length - 1;
  
  return (
    <ul style={{position: 'relative'}}>
      {updatedList.map((item, index) => {
        const top = (height * (index + start)) + 'px';
        const refVal = getReference(index, index === lastIndex);
        const id = index === 0 ? 'top' : (index === lastIndex ? 'bottom' : '');
        return (<li className="li-card" key={item.key} style={{top}} ref={refVal} id={id}>{item.value}</li>);
      })}
    </ul>
  );
}
export { SlidingWindowScrollHook };

.li-card {
  list-style: none;
  box-shadow: 2px 2px 9px 0px #bbb;
  padding: 70px 10px;
  margin-bottom: 20px;
  border-radius: 10px;
  position: absolute;
  left: 30px;
  width: 80%;
}

$('a').href;
$('[test-id="logo-img"]').src;
$('#movie_player').click();

$$('.button')

var images = $$('img', document.querySelector('.devsite-header-background'));
   for (each in images) {
       console.log(images[each].src);
}

$x("//p")

$x("//p[a]")

getEventListeners(document);

const text = "文本1"
console.log(`打印${text}`)

console.log("打印 %s", text)

console.log('%c 文本1', 'font-size:50px; background: ; text-shadow: 10px 10px 10px blue')

const text = "文本1"
console.log('%c %s', 'font-size:50px; background: ; text-shadow: 10px 10px 10px blue', text)

console.log('%c Auth ', 
            'color: white; background-color: #2274A5', 
            'Login page rendered');
console.log('%c GraphQL ', 
            'color: white; background-color: #95B46A', 
            'Get user details');
console.log('%c Error ', 
            'color: white; background-color: #D33F49', 
            'Error getting user details');

console.log('hello', hello);
console.log('world', world);

console.log({hello, world});

console.assert（assertion，obj）

const value = 1001
console.assert(value===1000,"value is not 1000")

console.group('用户列表');
console.log('name: 张三');
console.log('job: 🐶前端');
// 内层
console.group('地址');
console.log('Street: 123 街');
console.log('City: 北京');
console.log('State: 在职');
console.groupEnd(); // 结束内层
console.groupEnd(); // 结束外层

let i = 0;
console.time("While loop");
while (i < 1000000) {
  i++;
}
console.timeEnd("While loop");
console.time("For loop");
for (i = 0; i < 1000000; i++) {
  // For Loop
}
console.timeEnd("For loop");

let languages = [
    { name: "JavaScript", fileExtension: ".js" },
    { name: "TypeScript", fileExtension: ".ts" },
    { name: "CoffeeScript", fileExtension: ".coffee" }
];
console.table(languages);

console.log（"Why，hello!"）；
console.dir（"Why，hello!"）;

console.log(document)
console.dir(document)

$ openssl sha256 /Users/hiro/Downloads/非对称.png
SHA256(/Users/hiro/Downloads/非对称.png)= 7c264efc9ea7d0431e7281286949ec4c558205f690c0df601ff98d59fc3f4f64

# 源文本：
The quick brown fox jumps over the lazy dog

# 编码后：
#!shell
%54%68%65%20%71%75%69%63%6b%20%62%72%6f%77%6e%20%66%6f%78%20%6a%75%6d%70%73%20%6f%76%65%72%20%74%68%65%20%6c%61%7a%79%20%64%6f%67

function hello(name) {
  console.log('Hello, ' + name);
}

hello('New user');

var _0xa1cc=["\x48\x65\x6C\x6C\x6F\x2C\x20","\x6C\x6F\x67","\x4E\x65\x77\x20\x75\x73\x65\x72"];
function hello(_0x2cc8x2){console[_0xa1cc[1]](_0xa1cc[0]+ _0x2cc8x2)}hello(_0xa1cc[2])

<script src="https://unpkg.com/[email protected]"></script>

npm install rough-viz

npm install react-roughviz
npm install vue-roughviz

pip install roughviz

<div id="vis0"></div>
<div id="vis1"></div>

new roughViz.BarH(
  {
    element: '#vis0',
    title: "Vehicles I've Had",
    titleFontSize: '1.5rem',
    legend: false,
    margin: {top: 50, bottom: 100, left: 160, right: 0},
    data: {
      labels: ['1992 Ford Aerostar Van', '2013 Kia Rio', '1980 Honda CB 125s', '1992 Toyota Tercel'],
      values: [8, 4, 6, 2]
    },
    xLabel: 'Time Owned (Years)',
    strokeWidth: 2,
    fillStyle: 'zigzag-line',
    highlight: 'gold',
  }
);

  new roughViz.BarH(
    {
      element: '#vis1',
      titleFontSize: '1.5rem',
      data: 'https://raw.githubusercontent.com/jwilber/random_data/master/owTanks.csv'
      color: 'tan',
      labels: 'name',
      values: 'health',
      title: "Overwatch Tank Health",
      roughness: 4,
    }
  );

<script src="https://aframe.io/releases/0.9.0/aframe.min.js"></script>
<script src="https://rawgit.com/jeromeetienne/ar.js/master/aframe/build/aframe-ar.js"></script>
<script>THREEx.ArToolkitContext.baseURL = 'https://rawgit.com/jeromeetienne/ar.js/master/three.js/'</script>

<body style='margin : 0px; overflow: hidden;'>
    <a-scene embedded arjs='sourceType: webcam; debugUIEnabled: false;'>
        <a-marker type='pattern' url='res/pattern-marker.patt'>
            <a-entity position='-3 2 0' text="width: 5; value:I am Psyduck. We are pokemon. We love you"></a-entity>
            <a-entity position='0 0 0' gltf-model="url(res/scene.gltf)"></a-entity>
        </a-marker>
    </a-scene>
</body>

const options = {
    root: document.querySelector('.scrollContainer'),
    rootMargin: '0px',
    threshold: [0.3, 0.5, 0.8, 1] }
    
const observer = new IntersectionObserver(handler, options)

function handler (entries, observer) { 
    entries.forEach(entry => { 
    // 每个成员都是一个IntersectionObserverEntry对象。
    // 举例来说，如果同时有两个被观察的对象的可见性发生变化，entries数组就会有两个成员。
    // entry.boundingClientRect 
    // entry.intersectionRatio 
    // entry.intersectionRect 
    // entry.isIntersecting 
    // entry.rootBounds 
    // entry.target 
    // entry.time 
    }); 
}

const target = document.querySelector(“.targetBox”); 
observer.observe(target);

observer.unobserve(target)

observer.disconnect()

<img src="placeholder.png" data-src="img-1.jpg">
<img src="placeholder.png" data-src="img-2.jpg">
<img src="placeholder.png" data-src="img-3.jpg">
<!-- more images -->

let observer = new IntersectionObserver(
(entries, observer) => { 
entries.forEach(entry => {
    /* 替换属性 */
    entry.target.src = entry.target.dataset.src;
    observer.unobserve(entry.target);
  });
}, 
{rootMargin: "0px 0px -200px 0px"});

document.querySelectorAll('img').forEach(img => { observer.observe(img) });

const boxList = [...document.querySelectorAll('.box')]

var io = new IntersectionObserver((entries) =>{
  entries.forEach(item => {
    // intersectionRatio === 1说明该元素完全暴露出来，符合业务需求
    if (item.intersectionRatio === 1) {
      // 。。。 埋点曝光代码
      io.unobserve(item.target)
    }
  })
}, {
  root: null,
  threshold: 1, // 阀值设为1，当只有比例达到1时才触发回调函数
})

// observe遍历监听所有box节点
boxList.forEach(box => io.observe(box))

<video src="OSRO-animation.mp4" controls=""></video>

let video = document.querySelector('video');
let isPaused = false; /* Flag for auto-paused video */
let observer = new IntersectionObserver((entries, observer) => { 
  entries.forEach(entry => {
    if(entry.intersectionRatio!=1  && !video.paused){
      video.pause(); isPaused = true;
    }
    else if(isPaused) {video.play(); isPaused=false}
  });
}, {threshold: 1});
observer.observe(video);

DOMAttributeNameChanged
DOMCharacterDataModified
DOMElementNameChanged
DOMNodeInserted
DOMNodeInsertedIntoDocument
DOMNodeRemoved
DOMNodeRemovedFromDocument
DOMSubtreeModified

let observer = new MutationObserver(callback);

function callback (mutations, observer) {
  mutations.forEach(function(mutation) {
    console.log(mutation);
  });
});

MutationObserver.observe(dom, options)

mutationObserver.observe(content, {
    attributes: true, // Boolean - 观察目标属性的改变
    characterData: true, // Boolean - 观察目标数据的改变(改变前的数据/值)
    childList: true, // Boolean - 观察目标子节点的变化，比如添加或者删除目标子节点，不包括修改子节点以及子节点后代的变化
    subtree: true, // Boolean - 目标以及目标的后代改变都会观察
    attributeOldValue: true, // Boolean - 表示需要记录改变前的目标属性值
    characterDataOldValue: true, // Boolean - 设置了characterDataOldValue可以省略characterData设置
    // attributeFilter: ['src', 'class'] // Array - 观察指定属性
});

MutationObserver.disconnect()

MutationObserver.takeRecords()

const target = document.getElementById('target-id')

const observer = new MutationObserver(records => {
  // 输入变更记录
})

// 开始观察
observer.observe(target, {
  characterData: true
})

var targetNode = document.querySelector('#kolor-kolor');
var config = { attributes: true };
var callback = function(mutationsList, observer) {
    if (mutationsList[0].type == 'attributes') {
        console.log('attribute change!');
        let ans = document.querySelector('#kolor-kolor').style.backgroundColor;
        document.querySelectorAll('#kolor-options a').forEach( (e) => {
            if (e.style.backgroundColor == ans) {
                e.text = 'Ans!';
                e.click()
            }
        })
    }
};

var observer = new MutationObserver(callback);
observer.observe(targetNode, config);

let observer = new ResizeObserver(callback);

const callback = entries => {
    entries.forEach(entry => {
        
    })
}

observer.observe(document.body)

observer.unobserve(document.body)

observer.disconnect(document.body)

<div class="box">
    <h3 class="info"></h3>
</div>
<div class="box small">
    <h3 class="info"></h3>
</div>

body {
    width: 100vw;
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 2vw;
    box-sizing: border-box;
}
.box {
    text-align: center;
    height: 20vh;
    border-radius: 8px;
    box-shadow: 0 0 4px rgba(0,0,0,.25);
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 1vw
}
.box h3 {
    color: #fff;
    margin: 0;
    font-size: 5vmin;
    text-shadow: 0 0 10px rgba(0,0,0,0.4);
}
.box.small {
    max-width: 550px;
    margin: 1rem auto;
}

const boxes = document.querySelectorAll('.box');
let callbackFired = 0;
const myObserver = new ResizeObserver(entries => {
    for (let entry of entries) {
        callbackFired++
        const infoEl = entry.target.querySelector('.info');
        const width = Math.floor(entry.contentRect.width);
        const height = Math.floor(entry.contentRect.height);
        const angle = Math.floor(width / 360 * 100);
        const gradient = `linear-gradient(${ angle }deg, rgba(0,143,104,1) 50%, rgba(250,224,66,1) 50%)`;
        entry.target.style.background = gradient;
        infoEl.innerText = `
        I'm ${ width }px and ${ height }px tall
        Callback fired: ${callbackFired}
        `;
    }
});
boxes.forEach(box => {
    myObserver.observe(box);
});

@media only screen and (max-width: 576px) {
  .post__item {
    flex-direction: column;
  }
  
  .post__image {
    flex: 0 auto;
    height: auto;
  }
}

let observer = new PerformanceObserver(callback); 

const callback = (list, observer) => {
   const entries = list.getEntries();
   entries.forEach((entry) => {
    console.log(“Name: “ + entry.name + “, Type: “ + entry.entryType + “, Start: “ + entry.startTime + “, Duration: “ + entry.duration + “\n”); });
}

observer.observe({entryTypes: ["entryTypes"]});

function filterTime(a, b) {
  return (a > 0 && b > 0 && (a - b) >= 0) ? (a - b) : undefined;
}

let resolvePerformanceTiming = (timing) => {
  let o = {
    initiatorType: timing.initiatorType,
    name: timing.name,
    duration: parseInt(timing.duration),
    redirect: filterTime(timing.redirectEnd, timing.redirectStart), // 重定向
    dns: filterTime(timing.domainLookupEnd, timing.domainLookupStart), // DNS解析
    connect: filterTime(timing.connectEnd, timing.connectStart), // TCP建连
    network: filterTime(timing.connectEnd, timing.startTime), // 网络总耗时

    send: filterTime(timing.responseStart, timing.requestStart), // 发送开始到接受第一个返回
    receive: filterTime(timing.responseEnd, timing.responseStart), // 接收总时间
    request: filterTime(timing.responseEnd, timing.requestStart), // 总时间

    ttfb: filterTime(timing.responseStart, timing.requestStart), // 首字节时间
  };

  return o;
};

let resolveEntries = (entries) => entries.map(item => resolvePerformanceTiming(item));

let resources = {
  init: (cb) => {
    let performance = window.performance || window.mozPerformance || window.msPerformance || window.webkitPerformance;
    if (!performance || !performance.getEntries) {
      return void 0;
    }

    if (window.PerformanceObserver) {
      let observer = new window.PerformanceObserver((list) => {
        try {
          let entries = list.getEntries();
          cb(resolveEntries(entries));
        } catch (e) {
          console.error(e);
        }
      });
      observer.observe({
        entryTypes: ['resource']
      })
    } else {
        window.addEventListener('load', () => {
        let entries = performance.getEntriesByType('resource');
        cb(resolveEntries(entries));
      });
    }
  },
};

npm install -g @vue/cli
# OR
yarn global add @vue/cli

<template>
  <div class="hello">
    <h1>{{ msg }}</h1>
    <!-- 省略 -->
  </div>
</template>

<script lang="ts">
import { Component, Prop, Vue } from 'vue-property-decorator';

@Component
export default class HelloWorld extends Vue {
  @Prop() private msg!: string;
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped></style>

// 数字，二、八、十六进制都支持
let decLiteral: number = 6;
let hexLiteral: number = 0xf00d;

// 字符串，单双引都行
let name: string = "bob";
let sentence: string = `Hello, my name is ${ name }.

// 数组，第二种方式是使用数组泛型，Array<元素类型>：
let list: number[] = [1, 2, 3];
let list: Array<number> = [1, 2, 3];

let u: undefined = undefined;
let n: null = null;

// 默认情况从0开始为元素编号，也可手动为1开始
enum Color {Red = 1, Green = 2, Blue = 4}
let c: Color = Color.Green;

let colorName: string = Color[2];
console.log(colorName);  // 输出'Green'因为上面代码里它的值是2

let person: any = "前端劝退师"
person = 25
person = true

let someValue: any = "this is a string";

let strLength: number = (<string>someValue).length;
let strLength: number = (someValue as string).length;

function getLength(something: string | number): number {
    return something.length;
}

// index.ts(2,22): error TS2339: Property 'length' does not exist on type 'string | number'.
//   Property 'length' does not exist on type 'number'.

function getLength(something: string | number): number {
    if ((<string>something).length) {
        return (<string>something).length;
    } else {
        return something.toString().length;
    }
}

function gen_func1<T>(arg: T): T {
    return arg;
}
// 或者
let gen_func2: <T>(arg: T) => T = function (arg) {
    return arg;
}

gen_func1<string>('Hello world');
gen_func2('Hello world'); 
// 第二种调用方式可省略类型参数，因为编译器会根据传入参数来自动识别对应的类型。

// 方法一：带有any参数的方法
function any_func(arg: any): any {
    console.log(arg.length);
		return arg;
}

// 方法二：Array泛型方法
function array_func<T>(arg: Array<T>): Array<T> {
	  console.log(arg.length);
		return arg;
}

interface Generics_interface<T> {
    (arg: T): T;
}
 
function func_demo<T>(arg: T): T {
    return arg;
}

let func1: Generics_interface<number> = func_demo;
func1(123);     // 正确类型的实际参数
func1('123');   // 错误类型的实际参数

interface User {
  name: string
  age: number
}

type User = {
  name: string
  age: number
};

interface SetUser {
  (name: string, age: number): void;
}
type SetUser = (name: string, age: number): void;

interface Name { 
  name: string; 
}
interface User extends Name { 
  age: number; 
}

type Name = { 
  name: string; 
}
type User = Name & { age: number  };

type Name = { 
  name: string; 
}
interface User extends Name { 
  age: number; 
}

interface Name { 
  name: string; 
}
type User = Name & { 
  age: number; 
}

// 基本类型别名
type Name = string

// 联合类型
interface Dog {
    wong();
}
interface Cat {
    miao();
}

type Pet = Dog | Cat

// 具体定义数组每个位置的类型
type PetList = [Dog, Pet]

// 当你想获取一个变量的类型时，使用 typeof
let div = document.createElement('div');
type B = typeof div

type StringOrNumber = string | number;  
type Text = string | { text: string };  
type NameLookup = Dictionary<string, Person>;  
type Callback<T> = (data: T) => void;  
type Pair<T> = [T, T];  
type Coordinates = Pair<number>;  
type Tree<T> = T | { left: Tree<T>, right: Tree<T> };

interface User {
  name: string
  age: number
}

interface User {
  sex: string
}

/*
User 接口为 {
  name: string
  age: number
  sex: string 
}
*/

interface Person {
  name: string;
  age?: number;
  gender?: number;
}

interface User {
    readonly loginName: string;
    password: string;
}

interface IDeveloper {
   name: string;
   age?: number;
}
// OK
class dev implements IDeveloper {
    name = 'Alex';
    age = 20;
}
// OK
class dev2 implements IDeveloper {
    name = 'Alex';
}
// Error
class dev3 implements IDeveloper {
    name = 'Alex';
    age = '9';
}

 class A extends B implements C,D,E

// shims-tsx.d.ts
import Vue, { VNode } from 'vue';

declare global {
  namespace JSX {
    // tslint:disable no-empty-interface
    interface Element extends VNode {}
    // tslint:disable no-empty-interface
    interface ElementClass extends Vue {}
    interface IntrinsicElements {
      [elem: string]: any;
    }
  }
}

// shims-vue.d.ts
declare module '*.vue' {
  import Vue from 'vue';
  export default Vue;
}

declare var 声明全局变量
declare function 声明全局方法
declare class 声明全局类
declare enum 声明全局枚举类型
declare global 扩展全局变量
declare module 扩展模块

declare namespace D3{
    export interface Selectors { ... }
}
declare var d3: D3.Base;

function buildName(firstName: string, lastName?: string) {
    return firstName + ' ' + lastName
}

// 错误演示
buildName("firstName", "lastName", "lastName")
// 正确演示
buildName("firstName")
// 正确演示
buildName("firstName", "lastName")

let s = e!.name;  // 断言e是非空并访问name属性

  import Vue from 'vue'

  const Component = Vue.extend({
  	// type inference enabled
  })

import { Component, Vue, Prop } from 'vue-property-decorator'

@Component
export default class Test extends Vue {
  @Prop({ type: Object })
  private test: { value: string }
}

<template>
  <div class="hello">
    <h1>{{ msg }}</h1>
    <!-- 省略 -->
  </div>
</template>

<script lang="ts">
import { Component, Prop, Vue } from 'vue-property-decorator';

@Component
export default class HelloWorld extends Vue {
  @Prop() private msg!: string;
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped></style>

import {componentA,componentB} from '@/components';

export default {
	components: { componentA, componentB},
	props: {
    propA: { type: Number },
    propB: { default: 'default value' },
    propC: { type: [String, Boolean] },
  }
  // 组件数据
  data () {
    return {
      message: 'Hello'
    }
  },
  // 计算属性
  computed: {
    reversedMessage () {
      return this.message.split('').reverse().join('')
    }
    // Vuex数据
    step() {
    	return this.$store.state.count
    }
  },
  methods: {
    changeMessage () {
      this.message = "Good bye"
    },
    getName() {
    	let name = this.$store.getters['person/name']
    	return name
    }
  },
  // 生命周期
  created () { },
  mounted () { },
  updated () { },
  destroyed () { }
}

import { Component, Vue, Prop } from 'vue-property-decorator';
import { State, Getter } from 'vuex-class';
import { count, name } from '@/person'
import { componentA, componentB } from '@/components';

@Component({
    components:{ componentA, componentB},
})
export default class HelloWorld extends Vue{
	@Prop(Number) readonly propA!: number | undefined
  @Prop({ default: 'default value' }) readonly propB!: string
  @Prop([String, Boolean]) readonly propC!: string | boolean | undefined
  
  // 原data
  message = 'Hello'
  
  // 计算属性
	private get reversedMessage (): string[] {
  	return this.message.split('').reverse().join('')
  }
  // Vuex 数据
  @State((state: IRootState) => state . booking. currentStep) step!: number
	@Getter( 'person/name') name!: name
  
  // method
  public changeMessage (): void {
    this.message = 'Good bye'
  },
  public getName(): string {
    let storeName = name
    return storeName
  }
	// 生命周期
  private created ()：void { },
  private mounted ()：void { },
  private updated ()：void { },
  private destroyed ()：void { }
}

import Vue from 'vue';
import App from './App.vue';
import router from './router';
import store from './store';

Vue.config.productionTip = false;

new Vue({
  router,
  store,
  render: (h) => h(App),
}).$mount('#app');

import Vue from 'vue';
import App from './App.vue';
import router from './router';
import store from './store';
// 新模块
import i18n from './i18n';

Vue.config.productionTip = false;

new Vue({
    router, 
    store, 
    i18n, // 新模块
    render: (h) => h(App),
}).$mount('#app');

// 声明全局方法
declare module 'vue/types/vue' {
  interface Vue {
        readonly $i18n: VueI18Next;
        $t: TranslationFunction;
    }
}

$ npm i axios vue-axios

import Vue from 'vue'
import axios from 'axios'
import VueAxios from 'vue-axios'

Vue.use(VueAxios, axios)

Vue.axios.get(api).then((response) => {
  console.log(response.data)
})

this.axios.get(api).then((response) => {
  console.log(response.data)
})

this.$http.get(api).then((response) => {
  console.log(response.data)
})

-api
    - main.ts   // 实际调用
-utils
    - request.ts  // 接口封装

import * as axios from 'axios';
import store from '@/store';
// 这里可根据具体使用的UI组件库进行替换
import { Toast } from 'vant';
import { AxiosResponse, AxiosRequestConfig } from 'axios';
 
 /* baseURL 按实际项目来定义 */
const baseURL = process.env.VUE_APP_URL;

 /* 创建axios实例 */
const service = axios.default.create({
    baseURL,
    timeout: 0, // 请求超时时间
    maxContentLength: 4000,
});

service.interceptors.request.use((config: AxiosRequestConfig) => {
    return config;
}, (error: any) => {
    Promise.reject(error);
});

service.interceptors.response.use(
    (response: AxiosResponse) => {
        if (response.status !== 200) {
            Toast.fail('请求错误！');
        } else {
            return response.data;
        }
    },
    (error: any) => {
        return Promise.reject(error);
    });
    
export default service;

export interface AjaxResponse {
    code: number;
    data: any;
    message: string;
}

// api/main.ts
import request from '../utils/request';

// get
export function getSomeThings(params:any) {
    return request({
        url: '/api/getSomethings',
    });
}

// post
export function postSomeThings(params:any) {
    return request({
        url: '/api/postSomethings',
        methods: 'post',
        data: params
    });
}

<template>
	<div class="blogpost">
		<h2>{{ post.title }}</h2>
		<p>{{ post.body }}</p>
		<p class="meta">Written by {{ post.author }} on {{ date }}</p>
	</div>
</template>

<script lang="ts">
import { Component, Prop, Vue } from 'vue-property-decorator';

// 在这里对数据进行类型约束
export interface Post {
	title: string;
	body: string;
	author: string;
	datePosted: Date;
}

@Component
export default class HelloWorld extends Vue {
	@Prop() private post!: Post;

	get date() {
		return `${this.post.datePosted.getDate()}/${this.post.datePosted.getMonth()}/${this.post.datePosted.getFullYear()}`;
	}
}
</script>

<style scoped>
h2 {
  text-decoration: underline;
}
p.meta {
  font-style: italic;
}
</style>

<template>
  <div class="home">
    <img alt="Vue logo" src="../assets/logo.png">
   	<HelloWorld v-for="blogPost in blogPosts" :post="blogPost" :key="blogPost.title" />
  </div>
</template>

<script lang="ts">
import { Component, Vue } from 'vue-property-decorator';
import HelloWorld, { Post } from '@/components/HelloWorld.vue'; // @ is an alias to /src

@Component({
  components: {
    HelloWorld,
  },
})
export default class Home extends Vue {
    private blogPosts: Post[] = [
        {
          title: 'My first blogpost ever!',
          body: 'Lorem ipsum dolor sit amet.',
          author: 'Elke',
          datePosted: new Date(2019, 1, 18),
        },
        {
          title: 'Look I am blogging!',
          body: 'Hurray for me, this is my second post!',
          author: 'Elke',
          datePosted: new Date(2019, 1, 19),
        },
        {
          title: 'Another one?!',
          body: 'Another one!',
          author: 'Elke',
          datePosted: new Date(2019, 1, 20),
        },
      ];
}
</script>

import React from 'react';
import PropTypes from 'prop-types';

import { FilesDragAndDrop } from '../components/Common/FilesDragAndDropHook';

export default class App extends React.Component {
    static propTypes = {};

    onUpload = (files) => {
        console.log(files);
    };

    render() {
        return (
            <div>
                <FilesDragAndDrop
                    onUpload={this.onUpload}
                />
            </div>
        );
    }
}

import React from 'react';
import PropTypes from 'prop-types';

import '../../scss/components/Common/FilesDragAndDrop.scss';

export default class FilesDragAndDrop extends React.Component {
    static propTypes = {
        onUpload: PropTypes.func.isRequired,
    };

    render() {
        return (
            <div className='FilesDragAndDrop__area'>
                传下文件试试？
                <span
                    role='img'
                    aria-label='emoji'
                    className='area__icon'
                >
                    &#128526;
                </span>
            </div>
        );
    }
}

import React, { useEffect, useState, useRef } from "react";
import PropTypes from 'prop-types';
import classNames from 'classnames';
import classList from '../../scss/components/Common/FilesDragAndDrop.scss';
const FilesDragAndDrop = (props) => {
    return (
        <div className='FilesDragAndDrop__area'>
            传下文件试试？
            <span
                role='img'
                aria-label='emoji'
                className='area__icon'
            >
                &#128526;
            </span>
        </div>
    );
}

FilesDragAndDrop.propTypes = {
    onUpload: PropTypes.func.isRequired,
    children: PropTypes.node.isRequired,
    count: PropTypes.number,
    formats: PropTypes.arrayOf(PropTypes.string)
}

export { FilesDragAndDrop };

.FilesDragAndDrop {
  .FilesDragAndDrop__area {
    width: 300px;
    height: 200px;
    padding: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-flow: column nowrap;
    font-size: 24px;
    color: #555555;
    border: 2px #c3c3c3 dashed;
    border-radius: 12px;

    .area__icon {
      font-size: 64px;
      margin-top: 20px;
    }
  }
}

const refContainer = useRef(initialValue);

...
const drop = useRef();

return (
    <div
        ref={drop}
        className='FilesDragAndDrop'
    />
    ...
    )

e.preventDefault() //阻止事件的默认行为(如在浏览器打开文件)
e.stopPropagation() // 阻止事件冒泡

const handleDragOver = (e) => {
    // e.preventDefault();
    // e.stopPropagation();
};

state = {
    dragging: false,
    message: {
        show: false,
        text: null,
        type: null,
    },
};

const [属性, 操作属性的方法] = useState(默认值);

const [dragging, setDragging] = useState(false);
const [message, setMessage] = useState({ show: false, text: null, type: null });

const drop = useRef(); // 落下层
const drag = useRef(); // 拖拽活动层

<FilesDragAndDrop
    onUpload={this.onUpload}
    count={1}
    formats={['jpg', 'png']}
>
    <div className={classList['FilesDragAndDrop__area']}>
        传下文件试试？
<span
            role='img'
            aria-label='emoji'
            className={classList['area__icon']}
        >
            &#128526;
</span>
    </div>
</FilesDragAndDrop>

const handleDrop = (e) => {
    e.preventDefault();
    e.stopPropagation();
    setDragging(false)
    const { count, formats } = props;
    const files = [...e.dataTransfer.files];
    if (count && count < files.length) {
        showMessage(`抱歉，每次最多只能上传${count} 文件。`, 'error', 2000);
        return;
    }
    if (formats && files.some((file) => !formats.some((format) => file.name.toLowerCase().endsWith(format.toLowerCase())))) {
        showMessage(`只允许上传 ${formats.join(', ')}格式的文件`, 'error', 2000);
        return;
    }
    if (files && files.length) {
        showMessage('成功上传！', 'success', 1000);
        props.onUpload(files);
    }
};

const showMessage = (text, type, timeout) => {
    setMessage({ show: true, text, type, })
    setTimeout(() =>
        setMessage({ show: false, text: null, type: null, },), timeout);
};

componentDidMount () {
    this.drop.addEventListener('dragover', this.handleDragOver);
}

componentWillUnmount () {
    this.drop.removeEventListener('dragover', this.handleDragOver);
}

useEffect(() => {
  document.title = `You clicked ${count} times`;
}, [count]); // 仅在 count 更改时更新

useEffect(() => {
    drop.current.addEventListener('dragover', handleDragOver);
    return () => {
        drop.current.removeEventListener('dragover', handleDragOver);
    }
})

import React, { useEffect, useState, useRef } from "react";
import PropTypes from 'prop-types';
import classNames from 'classnames';
import classList from '../../scss/components/Common/FilesDragAndDrop.scss';

const FilesDragAndDrop = (props) => {
    const [dragging, setDragging] = useState(false);
    const [message, setMessage] = useState({ show: false, text: null, type: null });
    const drop = useRef();
    const drag = useRef();
    useEffect(() => {
        // useRef 的 drop.current 取代了 ref 的 this.drop
        drop.current.addEventListener('dragover', handleDragOver);
        drop.current.addEventListener('drop', handleDrop);
        drop.current.addEventListener('dragenter', handleDragEnter);
        drop.current.addEventListener('dragleave', handleDragLeave);
        return () => {
            drop.current.removeEventListener('dragover', handleDragOver);
            drop.current.removeEventListener('drop', handleDrop);
            drop.current.removeEventListener('dragenter', handleDragEnter);
            drop.current.removeEventListener('dragleave', handleDragLeave);
        }
    })
    const handleDragOver = (e) => {
        e.preventDefault();
        e.stopPropagation();
    };

    const handleDrop = (e) => {
        e.preventDefault();
        e.stopPropagation();
        setDragging(false)
        const { count, formats } = props;
        const files = [...e.dataTransfer.files];

        if (count && count < files.length) {
            showMessage(`抱歉，每次最多只能上传${count} 文件。`, 'error', 2000);
            return;
        }

        if (formats && files.some((file) => !formats.some((format) => file.name.toLowerCase().endsWith(format.toLowerCase())))) {
            showMessage(`只允许上传 ${formats.join(', ')}格式的文件`, 'error', 2000);
            return;
        }

        if (files && files.length) {
            showMessage('成功上传！', 'success', 1000);
            props.onUpload(files);
        }
    };

    const handleDragEnter = (e) => {
        e.preventDefault();
        e.stopPropagation();
        e.target !== drag.current && setDragging(true)
    };

    const handleDragLeave = (e) => {
        e.preventDefault();
        e.stopPropagation();
        e.target === drag.current && setDragging(false)
    };

    const showMessage = (text, type, timeout) => {
        setMessage({ show: true, text, type, })
        setTimeout(() =>
            setMessage({ show: false, text: null, type: null, },), timeout);
    };

    return (
        <div
            ref={drop}
            className={classList['FilesDragAndDrop']}
        >
            {message.show && (
                <div
                    className={classNames(
                        classList['FilesDragAndDrop__placeholder'],
                        classList[`FilesDragAndDrop__placeholder--${message.type}`],
                    )}
                >
                    {message.text}
                    <span
                        role='img'
                        aria-label='emoji'
                        className={classList['area__icon']}
                    >
                        {message.type === 'error' ? <>&#128546;</> : <>&#128536;</>}
                    </span>
                </div>
            )}
            {dragging && (
                <div
                    ref={drag}
                    className={classList['FilesDragAndDrop__placeholder']}
                >
                    请放手
                    <span
                        role='img'
                        aria-label='emoji'
                        className={classList['area__icon']}
                    >
                        &#128541;
                    </span>
                </div>
            )}
            {props.children}
        </div>
    );
}

FilesDragAndDrop.propTypes = {
    onUpload: PropTypes.func.isRequired,
    children: PropTypes.node.isRequired,
    count: PropTypes.number,
    formats: PropTypes.arrayOf(PropTypes.string)
}

export { FilesDragAndDrop };

import React, { Component } from 'react';
import { FilesDragAndDrop } from '../components/Common/FilesDragAndDropHook';
import classList from '../scss/components/Common/FilesDragAndDrop.scss';

export default class App extends Component {
    onUpload = (files) => {
        console.log(files);
    };
    render () {
        return (
            <FilesDragAndDrop
                onUpload={this.onUpload}
                count={1}
                formats={['jpg', 'png', 'gif']}
            >
                <div className={classList['FilesDragAndDrop__area']}>
                    传下文件试试？
            <span
                        role='img'
                        aria-label='emoji'
                        className={classList['area__icon']}
                    >
                        &#128526;
            </span>
                </div>
            </FilesDragAndDrop>
        )
    }
}

.FilesDragAndDrop {
  position: relative;

  .FilesDragAndDrop__placeholder {
    position: absolute;
    top: 0;