Escape a regular expression string or pattern.
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> Escape a [regular expression][mdn-regexp] string or pattern.
``bash`
npm install @stdlib/utils-escape-regexp-string
`javascript`
var rescape = require( '@stdlib/utils-escape-regexp-string' );
#### rescape( str )
Escapes a [regular expression][mdn-regexp] string or pattern.
`javascript
var str = rescape( '/[A-Z]*/' );
// returns '/\[A\-Z\]\*/'
str = rescape( '[A-Z]*' );
// returns '\[A\-Z\]\*'
`
- The following characters have special meaning inside of regular expressions and need to be escaped in case the characters should be treated literally:
| description | value |
| ------------- | -------- |
| Backslash | \ |{ }
| Braces | |[ ]
| Brackets | |^
| Caret | |$
| Dollar Sign | |/
| Forward Slash | |*
| Asterisk | |( )
| Parentheses | |.
| Period | |+
| Plus Sign | ||
| Vertical Bar | |?
| Question Mark | |
- If the function is provided a value which is not a string, the function throws an error.
`javascript
var rescape = require( '@stdlib/utils-escape-regexp-string' );
var out = rescape( '/beep/' );
// returns '/beep/'
out = rescape( 'beep' );
// returns 'beep'
out = rescape( '/[A-Z]*/' );
// returns '/\[A\-Z\]\*/'
out = rescape( '[A-Z]*' );
// returns '\[A\-Z\]\*'
out = rescape( '/\\\//ig' );
// returns '/\\\//ig'
out = rescape( '\\\/' );
// returns '\\\/'
out = rescape( '/[A-Z]{0,}/' );
// returns '/\[A\-Z\]\{0,\}/'
out = rescape( '[A-Z]{0,}' );
// returns '\[A\-Z\]\{0,\}'
out = rescape( '/^boop$/' );
// returns '/\^boop\$/'
out = rescape( '^boop$' );
// returns '\^boop\$'
out = rescape( '/(?:.*)/' );
// returns '/\(\?:\.\*\)/'
out = rescape( '(?:.*)' );
// returns '\(\?:\.\*\)'
out = rescape( '/(?:beep|boop)/' );
// returns '/\(\?:beep\|boop\)/'
out = rescape( '(?:beep|boop)' );
// returns '\(\?:beep\|boop\)'
`
*
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
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---
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Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
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[mdn-regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions