Micro parser for detection of literal regexes

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1.0.25 years ago7 years agoMinified + gzip package size for skip-regex in KB


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Micro parser for detection of literal regexes.
  • Fast detection with high accuracy.
  • Minimum size.
  • Compatible with NodeJS, bundlers, IE9+, and modern Browsers.
  • TypeScript definition.
  • Zero dependencies.


npm install skip-regex --save
# or
yarn add skip-regex

or load the global skipRegex function in your browser:
<script src=""></script>

Three formats transpiled to ES5:
  • CommonJS for node.js and browserify-like bundlers.
  • ESM for bundlers like Rollup.
  • UMD for AMD, CommonJS, and browsers.


skipRegex(source: string, start: number) => number

The start position must point to a slash within source.
From there, skipRegex will find the end of a regular expression in the given string.
The returned value is the position of the character following the regex, or start+1 if the slash does not start a regex.


This is a silly example, but it will give the idea.
import skipRegex from 'skip-regex'

const source = ' /.*/ '
const start  = source.indexOf('/')

if (~start) {
  const end = skipRegex(source, start)

  if (end > start + 1) {      // detected as regex?
    const regex = source.slice(start, end)
    console.log(`Found regex ${regex} at position ${start}!`)

  } else if (source[end] === '*' || source[end] === '/') {
    console.log('The slash starts a JS comment.')

  } else {
    console.log('The slash is a division sign.')

For something more complete see the js-cleanup code, an utility to clean comments safely in JS-like sources, which uses skip-regex to skip regular expressions.
For Rollup, you can use rollup-plugin-node-resolve to resolve 'skip-regex' as an ES6 module.
For TypeScript, enable esModuleInterop in your tsconfig.json or use the "import=require" syntax:
import skipRegex = require('skip-regex')


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The MIT license (MIT)
© 2018 Alberto Martínez