replaceBeforeLast

Replace the substring before the last occurrence of a specified search string.

Usage

var replaceBeforeLast = require( '@stdlib/string/base/replace-before-last' );

replaceBeforeLast( str, search, replacement, fromIndex )

Replaces the substring before the last occurrence of a specified search string.

var str = 'beep boop';
var out = replaceBeforeLast( str, ' ', 'loop', str.length );
// returns 'loop boop'

out = replaceBeforeLast( str, 'o', 'bar', str.length );
// returns 'barop'

To begin searching from a specific index, provide a corresponding fromIndex argument.

var out = replaceBeforeLast( 'beep boop beep', ' ', 'loop', 5 );
// returns 'loop boop beep'

If fromIndex is less than zero, the starting index is resolved relative to the last string character, with the last string character corresponding to fromIndex = -1.

var out = replaceBeforeLast( 'beep boop beep', ' ', 'loop', -1 );
// returns 'loop beep'

Notes

If a search string is not present in a provided string, the function returns the provided string unchanged.
If a search string is an empty string, the function returns the provided string unchanged.
If fromIndex resolves to an index which is less than 0, the function returns the provided string unchanged.

Examples

var replaceBeforeLast = require( '@stdlib/string/base/replace-before-last' );

var str = 'beep boop';
var out = replaceBeforeLast( str, 'p', 'see', str.length );
// returns 'seep'

str = 'Hello World!';
out = replaceBeforeLast( str, 'xyz', 'foo', str.length );
// returns 'Hello World!'

str = 'Hello World!';
out = replaceBeforeLast( str, '', 'foo', str.length );
// returns 'Hello World!'

str = '';
out = replaceBeforeLast( str, 'xyz', 'foo', str.length );
// returns ''