balanced string matching, and replacing.
npm install node-balanced
lets say you have
{
@hello 1 {
a {
}
}
@hello 2 {
a {
}
}
@hello 3 {
a {
}
}
}and you would like to replace the @hello block easily, balanced allows you to do this
var balanced = require('node-balanced');
balanced.replacements({
source: source,
head: /@hello \d \{/, // optional (defalut: open)
open: '{',
close: '}',
balance: false, // optional (default: false)
exceptions: false, // optional (default: false)
replace: function (source, head, tail) {
return head + source + tail;
}
});this is a simple and efficient way to make balanced replacements, without a parser.
lets say you have some bad html but the html you're trying to match is valid you could do this
balanced.matches({
source: html,
head: /<div[^>]*class="[^"]*myclassname[^"]*"[^>]*>/,
open: /<div[^>]*>/,
close: '</div>'
});you can get balanced matches by doing the following
var balanced = require('node-balanced');
balanced.matches({
source: source,
head: /@hello \d \{/, // optional (defalut: open)
open: '{',
close: '}',
balance: false, // optional (default: false) when set to true it will return `null` when there is an error
exceptions: false // optional (default: false),
ignore: [] // array of ignore ranges/matches
});you can match multiple head/open/close efficiently by doing this
var isBalanced = balanced.matches({
source: '{[({)]}}',
open: ['{', '[', '('],
close: ['}', ']', ')'],
balance: true
});ignore is supported by the matches and replacements methods, this is very useful for something like not matching inside of comments
var blockComments = balanced.matches({source: source, open: '/*', close: '*/'}),
singleLineComments = balanced.getRangesForMatch(source, /^\s*\/\/.+$/gim);
balanced.matches({
source: source,
head: /@hello \d \{/,
open: '{',
close: '}',
ignore: Array.prototype.concat.call([], blockComments, singleLineComments),
replace: function (source, head, tail) {
return head + source + tail;
}
});in this example we have code and we want to avoid replacing text thats inside of the multiline/singleline comments, and quotes
{
@hello 1 {
a {
}
}
/*
@hello 2 {
a {
}
}
*/
@hello 3 {
a {
}
}
// @hello 4 {}
}
var hello = "@hello 5 {}";with balanced you can do this
// returns quote ranges with option ignore filter
function getQuoteRanges (string, ignore) {
var quotes = balanced.getRangesForMatch(string, new RegExp('\'|"', 'g'));
// filter out ingored ranges
if (ignore) {
quotes = balanced.rangesWithout(quotes, ignore);
}
var currect = null,
ranges = [];
quotes.forEach(function (quote) {
if (currect && currect.match === quote.match) {
ranges.push({
index: currect.index,
length: quote.index - currect.index + 1
});
currect = null;
} else if (!currect) {
currect = quote;
}
});
return ranges;
}
var blockComments = balanced.matches({source: string, open: '/*', close: '*/'}),
singleLineComments = balanced.getRangesForMatch(string, /^\s*\/\/.+$/gim),
ignores = Array.prototype.concat.call([], blockComments, singleLineComments),
quotes = getQuoteRanges(string, ignores);
// remove ignores inside of quotes
ignores = balanced.rangesWithout(ignores, quotes);
// optional ignore code inside of quotes
ignores = ignores.concat(quotes);
// run your matches or replacements method
balanced.matches({
source: string,
head: /@hello \d \{/,
open: '{',
close: '}',
ignore: ignores
});as you can see by using these principles you can accomplish this kind of stuff easily
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent