@stdlib/string/base/for-each-grapheme-cluster/lib/main.js

String manipulation functions.

/**
* @license Apache-2.0
*
* Copyright (c) 2023 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var nextGraphemeClusterBreak = require( './../../../next-grapheme-cluster-break' );


// MAIN //

/**
* Invokes a function for each grapheme cluster (i.e., user-perceived character) in a string.
*
* @param {string} str - input string
* @param {Function} clbk - function to invoke
* @param {*} [thisArg] - execution context
* @returns {string} input string
*
* @example
* function log( value, index ) {
*     console.log( '%d: %s', index, value );
* }
*
* forEach( 'Hello', log );
*/
function forEach( str, clbk, thisArg ) {
	var len;
	var idx;
	var brk;

	len = str.length;
	idx = 0;
	while ( idx < len ) {
		brk = nextGraphemeClusterBreak( str, idx );
		if ( brk === -1 ) {
			brk = len;
		}
		clbk.call( thisArg, str.substring( idx, brk ), idx, str );
		idx = brk;
	}
	return str;
}


// EXPORTS //

module.exports = forEach;