time-to-botec

Benchmark sampling in different programming languages
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for_each_right.js (2362B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2018 The Stdlib Authors.
      5 *
      6 * Licensed under the Apache License, Version 2.0 (the "License");
      7 * you may not use this file except in compliance with the License.
      8 * You may obtain a copy of the License at
      9 *
     10 *    http://www.apache.org/licenses/LICENSE-2.0
     11 *
     12 * Unless required by applicable law or agreed to in writing, software
     13 * distributed under the License is distributed on an "AS IS" BASIS,
     14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15 * See the License for the specific language governing permissions and
     16 * limitations under the License.
     17 */
     18 
     19 'use strict';
     20 
     21 // MODULES //
     22 
     23 var isCollection = require( '@stdlib/assert/is-collection' );
     24 var isFunction = require( '@stdlib/assert/is-function' );
     25 
     26 
     27 // MAIN //
     28 
     29 /**
     30 * Invokes a function once for each element in a collection, iterating from right to left.
     31 *
     32 * ## Notes
     33 *
     34 * -   For dynamic array resizing, the only behavior made intentionally consistent with `forEach` (iterating from left to right) is when elements are pushed onto the beginning (end) of an array. In other words, for `forEach()`, `[].push()` behavior is consistent with `forEachRight()` `[].unshift()` behavior.
     35 *
     36 *
     37 * @param {Collection} collection - input collection
     38 * @param {Function} fcn - function to invoke
     39 * @param {*} [thisArg] - execution context
     40 * @throws {TypeError} first argument must be a collection
     41 * @throws {TypeError} second argument must be a function
     42 * @returns {Collection} input collection
     43 *
     44 * @example
     45 * function log( v, index, collection ) {
     46 *     console.log( '%s: %d', index, v );
     47 * }
     48 *
     49 * var arr = [ 1, 2, 3, 4 ];
     50 *
     51 * forEachRight( arr, log );
     52 */
     53 function forEachRight( collection, fcn, thisArg ) {
     54 	var len;
     55 	var i;
     56 	if ( !isCollection( collection ) ) {
     57 		throw new TypeError( 'invalid argument. First argument must be a collection. Value: `'+collection+'`.' );
     58 	}
     59 	if ( !isFunction( fcn ) ) {
     60 		throw new TypeError( 'invalid argument. Second argument must be a function. Value: `'+fcn+'`.' );
     61 	}
     62 	len = collection.length;
     63 	for ( i = len-1; i >= 0; i-- ) {
     64 		fcn.call( thisArg, collection[ i ], i, collection );
     65 
     66 		// Account for dynamically resizing a collection...
     67 		if ( len !== collection.length ) {
     68 			i += ( collection.length - len );
     69 			len = collection.length;
     70 		}
     71 	}
     72 	return collection;
     73 }
     74 
     75 
     76 // EXPORTS //
     77 
     78 module.exports = forEachRight;