swift

• 不需要main()函数做入口。
• let for const, var for let, 跟js不同

显示转换/隐示转换

• swift只有显示转换
• value to string:

let apple = 2
let appleSummary = "I have \(apple) apples."

• make null array, dict, let emptyArray = [String]() and let emptyDict = [String:Float]()

for loop

• there is for-in, for, while, repeat-while

if-switch

• if后必须是一个bool表达式

force unwrap

https://www.mokacoding.com/blog/impliticly-vs-force-unwrapping-swift-optionals/

Function

func greet(person: String) -> String{
  let greeting = "Hello, " + person + "!"
  return greeting
}

Closure闭包

https://www.zhihu.com/search?type=content&q=js%20%E9%97%AD%E5%8C%85

UIButton state

Swift foundation

protocol

private(set)

ERROR

• Ambiguous reference to operator function '>='
  https://stackoverflow.com/questions/38449252/ambiguous-reference-to-member

• 2019-06-11 13:56:09.121447+0900 GuessTheNumber[85183:6591564] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<GuessTheNumber.ViewController 0x7fba0dc07a30> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key resultLabel.'

• setTitle cannot used on UIbutton
  https://stackoverflow.com/questions/28591250/uibutton-settitle-doesnt-work

Error

• fatal error: Unexpectedly found nil while unwrapping an Optional value
  未登录identifier, 登陆identifier

emit-on

https://qiita.com/gitseitanaka/items/d708f3c955cbf8b2158f

• EventEmitter

Electron

• server: nodejs, front: chromium
• use HTML css, js to develop desktop application

monaco editor

use delete in JS

delete nameUsed[priviousNameIndex]

swift static initialize

static var initialYear: Int { return 1600 }

swift optional

• https://developer.apple.com/documentation/swift/optional

swift mutating

• method for struct, enum

delegate example

https://www.jianshu.com/p/c65f13683001

binding

• for reactive application or service

sql

erd

ddl

question

sqlの内部実行順序

cte使い方, subqueryとの違い

golang

method

func (b box) getSize() int{
  return b.length * b.width
}
// with pointer as receiver 
func (b *box) getSize() int{
  return b.length * b.width
}

• why use pointer as receiver, cause you wanna change the value

ctf

• skip <script> but <img src="123" onClick = "alert(1)"> cant ?
• ' make sql error

vue socket io error

• MetinSeylan/Vue-Socket.io#62
• uncaught type of class ???
• MetinSeylan/Vue-Socket.io#174

use of old version of npm

https://askubuntu.com/questions/1036278/npm-is-incorrect-version-on-latest-ubuntu-18-04-installation

link

ln -s /usr/local/bin/npm /usr/bin/npm

wsl file cannot edit by vscode

• microsoft/vscode#17860
• 由于用vue-cli或者其他脚手架生成的文件默认为root, 需要chrown来改成普通用户才能access

file permission of linux system

• microsoft/vscode#17860

vue client generate file, permission error

• unsolved

golang package management

• "github.com/woshahua" 全局path导入有效
• 导入 math/rand, can/rand 这类，需要在使用是用 crand can/rand 来区别。
• 如果文件中有go可执行文件 package名需要为main

babel for vue

• unsolved

set chrome headless

• https://qiita.com/tonio0720/items/70c13ad304154d95e4bc
• they just change the option
  -https://gist.github.com/anandsunderraman/e351485319a8a0e7df7e

express cannot use html

• https://qiita.com/take2k/items/8069b23bf06f7992419b

eslint recommand setting cant use console.log

• let system can use console.log
  https://stackoverflow.com/questions/34215526/eslint-how-to-disable-unexpected-console-statement-in-node-js

socketio broadcast.to.("room")

• 发送给除了自己以外的人

jquery focus

• https://www.sejuku.net/blog/41235

tableView ???

• dequeueReuseable
• didSelectRowAt
• identifier for tableView

newItem is a label

 func add(newItem item: ToDoItem) {
        items.append(item)
    }

get, set ??

• getter, setter used for public or private the operation of the value
  -https://qiita.com/codelynx/items/43e1c4f176730d952d13

swift _ in

tableView 滑动

web hook

segment fault

tech knowledge

• fatal error : 致命的错误。
• git rebase: something like merge
  https://git-scm.com/book/ja/v1/Git-%E3%81%AE%E3%83%96%E3%83%A9%E3%83%B3%E3%83%81%E6%A9%9F%E8%83%BD-%E3%83%AA%E3%83%99%E3%83%BC%E3%82%B9
• CROS
  • cant get server data by the file out of the server directory

类型

var counter;  // any type
var counter = 0; // number type, 推断
var counter: number; // number type
var counter: number = 0;

• null和undefined不能被当作类型使用.
• var作用域, let, const块作用域(常量)

联合类型

• var path: string[] | string;

类型守护

• like guard in swift
• use typeof and instanceof

next ---javascript

swift struct/class

• struct pass value, class pass pointer
• for array you can do

var a = [Int]()
a = [0]
a += [1, 2]  // a = [0,1,2]

弹出框

• UIAlertController

cocoapods

use MARK

//MARK: - Networking
/************************

//MARK: - JSON parsing
/************************

delegate委托

locationManager.delegate = self

info.list setting

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>NSLocationUsageDescription</key>
	<string>为了获取气象信息需要定位你当前的位置。</string>
	<key>NSLocationWhenInUseUsageDescription</key>
	<string>为了获取气象信息需要定位你当前的位置。</string>
    <key>NSAppTransportSecurity</key>
    <dict>
        <key>NSExceptionDomains</key>
        <dict>
            <key>openweathermap.org</key>
            <dict>
                <key>NSIncludesSubdomains</key>
                <true/>
                <key>NSTemporaryExceptionAllowsInsecureHTTPLoads</key>
                <true/>
            </dict>
        </dict>
    </dict>
	<key>CFBundleDevelopmentRegion</key>
	<string>$(DEVELOPMENT_LANGUAGE)</string>
	<key>CFBundleExecutable</key>
	<string>$(EXECUTABLE_NAME)</string>
	<key>CFBundleIdentifier</key>
	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
	<key>CFBundleInfoDictionaryVersion</key>
	<string>6.0</string>
	<key>CFBundleName</key>
	<string>$(PRODUCT_NAME)</string>
	<key>CFBundlePackageType</key>
	<string>APPL</string>
	<key>CFBundleShortVersionString</key>
	<string>1.0</string>
	<key>CFBundleVersion</key>
	<string>1</string>
	<key>LSRequiresIPhoneOS</key>
	<true/>
	<key>UILaunchStoryboardName</key>
	<string>LaunchScreen</string>
	<key>UIMainStoryboardFile</key>
	<string>Main</string>
	<key>UIRequiredDeviceCapabilities</key>
	<array>
		<string>armv7</string>
	</array>
	<key>UISupportedInterfaceOrientations</key>
	<array>
		<string>UIInterfaceOrientationPortrait</string>
	</array>
	<key>UISupportedInterfaceOrientations~ipad</key>
	<array>
		<string>UIInterfaceOrientationPortrait</string>
		<string>UIInterfaceOrientationPortraitUpsideDown</string>
		<string>UIInterfaceOrientationLandscapeLeft</string>
		<string>UIInterfaceOrientationLandscapeRight</string>
	</array>
</dict>
</plist>

closure swift

• 在闭包函数中一定要使用self来带入函数。

.double >

• 转换为double值

intValue, StringValue, int, string

pwa

@objc

• why this timer selector need objc

timer = Timer.scheduledTimer(timeInterval: 1, target: self,   selector: (#selector(ViewController.updateTimer)), userInfo: nil, repeats: true)

visual code 开发

• https://blog.csdn.net/q1056843325/article/details/89363550

api gateway

golang snippet vscode

缓存区溢出攻击

• https://www.zhihu.com/search?type=content&q=%E5%86%85%E5%AD%98%E6%B3%84%E6%BC%8F

glide not show image

kotlin standard library usage

• https://jamie.mccrindle.org/posts/exploring-kotlin-standard-library-part-3/

companion object

destroy{ view = nll} why we need this.

how to read file from asset android kotlin

kotlin lambda should be moved out of parenthesses

-https://www.reddit.com/r/Kotlin/comments/8x199t/intellij_lambda_argument_should_be_moved_out_of/

文件

• 文件就是字节序列，每个I/O设备，键盘，磁盘，甚至网络都可以看成是这样。系统中所有输入输出都是通过一小组成为Unix I/O的系统函数调用读写文件来实现的

clousure

• https://www.zhihu.com/search?type=content&q=%E9%97%AD%E5%8C%85
• 函数被声明并被带入时会保存区域内的变量

relogin terminal

• exec $SHELL -l

kotlin::class java

• class in kotlin stands for java class

null 安全

kotlin class need init ???

RecyclerView has no LayoutManager androidx.recyclerview.widget.RecyclerView

• https://stackoverflow.com/questions/27563853/java-lang-illegalstateexception-recyclerview-has-no-layoutmanager-in-fragment

hash -r