JarCastingskipRegex
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.
Install
npm install skip-regex --save
# or
yarn add skip-regex
or load the global skipRegex function in your browser:
<script src="https://unpkg.com/skip-regex/index.min.js"></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.
Syntax
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.
Example
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')
//...
Related Links
Some sites and tools that have been helpful:
- RegExp (Regular Expressions) Objects : ECMA Specs
- RegExp on MDN : MDN Reference
- RegEgg : Complete tutorial, various regex dialects
- RegExr : Online tool for learn and test regexes
- RegExp Preview and Editor : VSCode extension based on regexper-static
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Licence
The MIT license (MIT)
© 2018 Alberto Martínez