Package Exports

perf-regexes

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Readme

perf-regexes

Optimized and powerful regexes for JavaScript

Install

npm install perf-regexes --save

Included Regexes

Name	Description	Note
`JS_MLCMNT`	Valid multiline JS comment	Excludes invalid comments like `//`, supports nested `'/'`
`JS_SLCMNT`	Single line JS comment	From the `//` to the (but not including) next EOL
`JS_STRING`	Single and double quoted JS string	Handles nested quotes and escaped eols
`JS_REGEX`	Literal regex	Can match a divisor, so the match must be validated
`JS_REGEX_P`	Literal regex	Captures a prefix in $1, the regex is not captured
`HTML_CMNT`	Valid HTML comments	HTML comments with `<!--` and `-->` delimiters

All the regexes has the option 'g' and nothing more, so you can use it with exec or replace.

You don't need the option 'm', perf-regexes works with Win/Mac/Unix EOLs with no problems, but if you like use the RegExp constructor with the source property to recrate the regex like in the example.

NOTE:

Because the 'g', always set lastIndex before using a regex with the exec method.

Example

/*
  Comments removal made easy.
  ...but please don't use this for ES6 template strings
*/
const _R = require('perf-regexes')

function removeComments(source) {
  const re = new RegExp([
    _R.JS_MLCOMM.source,
    _R.JS_SLCOMM.source,
    _R.JS_STRING.source,
    _R.JS_REGEX_P.source].join('|'), 'gm');

  return source.replace(re, match => {
    return /^\/[/\*]/.test(match) ? ' ' : match
  })
}

Matching Regexes

It is not easy. Depending on code complexity, JS_REGEX_P can do the work with 99% accuracy, but you need handle the prefix captured in $1.

Also, this fail matching literal regexes starting with // or />, please follow the best-practices and use /\/ or /\>.

ES6 Template Strings

There's no secure way to match ES6 Template Literals with regexes.