substringBefore

Return the part of a string before a specified substring.

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

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