@isaacs/balanced-match

@isaacs/balanced-match

A hybrid CJS/ESM TypeScript fork of balanced-match.

Match balanced string pairs, like { and } or <b> and </b>. Supports regular expressions as well!

Example

Get the first matching pair of braces:

import { balanced } from '@isaacs/balanced-match'

console.log(balanced('{', '}', 'pre{in{nested}}post'))
console.log(balanced('{', '}', 'pre{first}between{second}post'))
console.log(balanced(/\s+\{\s+/, /\s+\}\s+/, 'pre  {   in{nest}   }  post'))

The matches are:

$ node example.js
{ start: 3, end: 14, pre: 'pre', body: 'in{nested}', post: 'post' }
{ start: 3,
  end: 9,
  pre: 'pre',
  body: 'first',
  post: 'between{second}post' }
{ start: 3, end: 17, pre: 'pre', body: 'in{nest}', post: 'post' }

API

const m = balanced(a, b, str)

For the first non-nested matching pair of a and b in str, return an object with those keys:

• start the index of the first match of a
• end the index of the matching b
• pre the preamble, a and b not included
• body the match, a and b not included
• post the postscript, a and b not included

If there's no match, undefined will be returned.

If the str contains more a than b / there are unmatched pairs, the first match that was closed will be used. For example, {{a} will match ['{', 'a', ''] and {a}} will match ['', 'a', '}'].

const r = balanced.range(a, b, str)

For the first non-nested matching pair of a and b in str, return an array with indexes: [ <a index>, <b index> ].

If there's no match, undefined will be returned.

If the str contains more a than b / there are unmatched pairs, the first match that was closed will be used. For example, {{a} will match [ 1, 3 ] and {a}} will match [0, 2].

Similar packages

Other packages similar to @isaacs/balanced-match

balanced

The 'balanced' package provides similar functionality to @isaacs/balanced-match, allowing you to find matching pairs of characters in a string. It offers a slightly different API and may have different performance characteristics.

brace-expansion

The 'brace-expansion' package is used for expanding brace patterns in strings, which involves finding and processing matching braces. While its primary purpose is different, it involves similar operations of matching pairs of characters.

parsimmon

Parsimmon is a library for writing parsers in JavaScript. It can be used to parse and match patterns in strings, including matching pairs of characters. It is more comprehensive and complex compared to @isaacs/balanced-match, as it is designed for building parsers.