balanced-match

What is balanced-match?

The balanced-match npm package is used to match balanced string pairs, such as brackets, tags, or any arbitrary string pairs within a given input string. It helps in parsing and manipulating strings where nested structures are present.

What are balanced-match's main functionalities?

Match Balanced Pairs

This feature allows you to find the first pair of balanced strings within a given input. In this example, it finds the outermost curly braces and returns the body and the tails of the match.

var balanced = require('balanced-match');
var result = balanced('{', '}', 'pre{in{nested}}post');
console.log(result);

Match Range

Similar to the first feature, but instead of returning the matched strings, it returns the range (indexes) of the outermost pair. This is useful when you need to manipulate the string based on its position.

var balanced = require('balanced-match');
var result = balanced.range('{', '}', 'pre{in{nested}}post');
console.log(result);

Other packages similar to balanced-match

brace-expansion

The brace-expansion package is similar to balanced-match in that it deals with matching patterns within strings, specifically brace expansion patterns. It is more specialized for brace pattern expansion and does not provide the generic balanced string matching capabilities of balanced-match.

README

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:

var balanced = require('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

var 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', '}'].

var 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].

Installation

With npm do:

npm install balanced-match

License

(MIT)

Copyright (c) 2013 Julian Gruber <[e-mail]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.