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Return the part of a string before a specified substring.
npm install @stdlib/string-substring-beforeAlternatively,
- To load the package in a website via a
scripttag without installation and bundlers, use the ES Module available on theesmbranch (see README). - If you are using Deno, visit the
denobranch (see README for usage intructions). - For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the
umdbranch (see README). - To use as a general utility for the command line, install the corresponding CLI package globally.
The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
var substringBefore = require( '@stdlib/string-substring-before' );Returns the part of a string before a specified substring.
var str = 'beep boop';
var out = substringBefore( str, ' ' );
// returns 'beep'
out = substringBefore( str, 'o' );
// returns 'beep b'- If a substring is not present in a provided string, the function returns the input string.
- If provided an empty substring, the function returns an empty string.
var substringBefore = require( '@stdlib/string-substring-before' );
var out = substringBefore( 'beep boop', 'p' );
// returns 'bee'
out = substringBefore( 'Hello World!', 'xyz' );
// returns 'Hello World!'
out = substringBefore( 'Hello World!', '' );
// returns ''
out = substringBefore( '', 'xyz' );
// returns ''To use as a general utility, install the CLI package globally
npm install -g @stdlib/string-substring-before-cliUsage: substring-before [options] --search=<string> [<string>]
Options:
-h, --help Print this message.
-V, --version Print the package version.
--search string Search string.
--split sep Delimiter for stdin data. Default: '/\\r?\\n/'.
-
If the split separator is a regular expression, ensure that the
splitoption is either properly escaped or enclosed in quotes.# Not escaped... $ echo -n $'foo\nbar\nbaz' | substring-before --search a --split /\r?\n/ # Escaped... $ echo -n $'foo\nbar\nbaz' | substring-before --search a --split /\\r?\\n/
-
The implementation ignores trailing delimiters.
$ substring-before abcdefg --search d
abcTo use as a standard stream,
$ echo -n $'beep\nboop' | substring-before --search p
bee
booBy default, when used as a standard stream, the implementation assumes newline-delimited data. To specify an alternative delimiter, set the split option.
$ echo -n 'beep\tboop' | substring-before --search p --split '\t'
bee
boo@stdlib/string-substring-before-last: return the part of a string before the last occurrence of a specified substring.@stdlib/string-substring-after: return the part of a string after a specified substring.@stdlib/string-substring-after-last: return the part of a string after the last occurrence of a specified substring.
This package is part of 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, see the main project repository.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.
