@stdlib/string/base/reverse-grapheme-clusters/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 //

/**
* Reverses the grapheme clusters (i.e., user-perceived characters) of a string.
*
* @param {string} str - input string
* @returns {string} output string
*
* @example
* var out = reverse( 'last man standing' );
* // returns 'gnidnats nam tsal'
*
* @example
* var out = reverse( 'presidential election' );
* // returns 'noitcele laitnediserp'
*
* @example
* var out = reverse( 'JavaScript' );
* // returns 'tpircSavaJ'
*
* @example
* var out = reverse( 'Hidden Treasures' );
* // returns 'serusaerT neddiH'
*
* @example
* var out = reverse( '🐶🐮🐷🐰🐸' );
* // returns '🐸🐰🐷🐮🐶'
*/
function reverse( str ) {
	var cluster;
	var out;
	var idx;
	var brk;
	var i;

	out = '';
	idx = 0;
	while ( idx < str.length ) {
		brk = nextGraphemeClusterBreak( str, idx );
		if ( brk === -1 ) {
			brk = str.length;
		}
		cluster = '';
		for ( i = idx; i < brk; i++ ) {
			cluster += str.charAt( i );
		}
		out = cluster + out;
		idx = brk;
	}
	return out;
}


// EXPORTS //

module.exports = reverse;