Return the previous extended grapheme cluster break in a string before a specified position.
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> Return the previous extended grapheme cluster break in a string before a specified position.
``bash`
npm install @stdlib/string-prev-grapheme-cluster-break
`javascript`
var prevGraphemeClusterBreak = require( '@stdlib/string-prev-grapheme-cluster-break' );
#### prevGraphemeClusterBreak( string\[, fromIndex] )
Returns the previous extended grapheme cluster break in a string before a specified position.
`javascript`
var out = prevGraphemeClusterBreak( 'last man standing' );
// returns 15
By default, the last extended grapheme cluster break in the string is returned. For the previous extended grapheme cluster break before a specified position in the string, provide a fromIndex.
`javascript`
var out = prevGraphemeClusterBreak( 'last man standing', 4 );
// returns 3
- If string is an empty string, the function returns -1 irrespective of fromIndex.fromIndex
- If there is no extended grapheme cluster break before , the function returns -1.fromIndex
- Note that does not refer to a visual character position, but to an index in the ordered sequence of [UTF-16][utf-16] code units.
`javascript
var prevGraphemeClusterBreak = require( '@stdlib/string-prev-grapheme-cluster-break' );
console.log( prevGraphemeClusterBreak( 'last man standing', 4 ) );
// => 3
console.log( prevGraphemeClusterBreak( 'presidential election', 8 ) );
// => 7
console.log( prevGraphemeClusterBreak( 'अनुच्छेद', 2 ) );
// => 0
console.log( prevGraphemeClusterBreak( '🌷', 1 ) );
// => -1
`
- [@stdlib/string-prev-grapheme-cluster-break-cli][@stdlib/string-prev-grapheme-cluster-break-cli]: CLI package for use as a command-line utility.
- [@stdlib/string-num-grapheme-clusters][@stdlib/string/num-grapheme-clusters]: return the number of grapheme clusters in a string.
- [@stdlib/string-next-grapheme-cluster-break][@stdlib/string/next-grapheme-cluster-break]: return the next extended grapheme cluster break in a string after a specified position.
*
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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[cli-url]: https://github.com/stdlib-js/string-prev-grapheme-cluster-break/tree/cli
[@stdlib/string-prev-grapheme-cluster-break]: https://github.com/stdlib-js/string-prev-grapheme-cluster-break/tree/main
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/string-prev-grapheme-cluster-break/tree/deno
[deno-readme]: https://github.com/stdlib-js/string-prev-grapheme-cluster-break/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/string-prev-grapheme-cluster-break/tree/umd
[umd-readme]: https://github.com/stdlib-js/string-prev-grapheme-cluster-break/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/string-prev-grapheme-cluster-break/tree/esm
[esm-readme]: https://github.com/stdlib-js/string-prev-grapheme-cluster-break/blob/esm/README.md
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[@stdlib/string/num-grapheme-clusters]: https://www.npmjs.com/package/@stdlib/string-num-grapheme-clusters
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