time-to-botec

Benchmark sampling in different programming languages
Log | Files | Refs | README

inmap_right.js (2584B)

      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 and updates the collection in-place, iterating from right to left.
     31 *
     32 * ## Notes
     33 *
     34 * -   For dynamic array resizing, the only behavior made intentionally consistent with `inmap` (iterating from left to right) is when elements are pushed onto the beginning (end) of an array. In other words, for `inmap()`, `[].push()` behavior is consistent with `inmapRight()` `[].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 scale( value, index, collection ) {
     46 *     console.log( '%s: %d', index, value );
     47 *     return value * index;
     48 * }
     49 *
     50 * var arr = [ 1, 2, 3, 4 ];
     51 *
     52 * var out = inmapRight( arr, scale );
     53 * // returns [ 0, 2, 6, 12 ]
     54 *
     55 * var bool = ( out === arr );
     56 * // returns true
     57 */
     58 function inmapRight( collection, fcn, thisArg ) {
     59 	var len;
     60 	var v;
     61 	var i;
     62 	if ( !isCollection( collection ) ) {
     63 		throw new TypeError( 'invalid argument. First argument must be a collection. Value: `'+collection+'`.' );
     64 	}
     65 	if ( !isFunction( fcn ) ) {
     66 		throw new TypeError( 'invalid argument. Second argument must be a function. Value: `'+fcn+'`.' );
     67 	}
     68 	len = collection.length;
     69 	for ( i = len-1; i >= 0; i-- ) {
     70 		v = fcn.call( thisArg, collection[ i ], i, collection );
     71 
     72 		// Account for dynamically resizing a collection...
     73 		if ( len !== collection.length ) {
     74 			i += ( collection.length - len );
     75 			len = collection.length;
     76 		}
     77 		if ( i >= 0 && i < len ) {
     78 			collection[ i ] = v;
     79 		}
     80 	}
     81 	return collection;
     82 }
     83 
     84 
     85 // EXPORTS //
     86 
     87 module.exports = inmapRight;