@stdlib/string-substring-before

Return the part of a string before a specified substring.

Usage no npm install needed!

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README

substringBefore

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Return the part of a string before a specified substring.

Installation

npm install @stdlib/string-substring-before

Usage

var substringBefore = require( '@stdlib/string-substring-before' );

substringBefore( str, search )

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'

Notes

  • 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.

Examples

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 ''

CLI

Installation

To use the module as a general utility, install the module globally

npm install -g @stdlib/string-substring-before

Usage

Usage: 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/'.

Notes

  • If the split separator is a regular expression, ensure that the split option 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.

Examples

$ substring-before abcdefg --search d
abc

To use as a standard stream,

$ echo -n 

beep\nboop' | substring-before --search p
bee
boo

By 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

See Also

Notice

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.

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License

See LICENSE.

Copyright

Copyright © 2016-2022. The Stdlib Authors.