/** * @license Apache-2.0 * * Copyright (c) 2018 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 isCollection = require( '@stdlib/assert/is-collection' ); var isFunction = require( '@stdlib/assert/is-function' ); // MAIN // /** * Invokes a function once for each element in a collection and updates the collection in-place, iterating from right to left. * * ## Notes * * - 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. * * * @param {Collection} collection - input collection * @param {Function} fcn - function to invoke * @param {*} [thisArg] - execution context * @throws {TypeError} first argument must be a collection * @throws {TypeError} second argument must be a function * @returns {Collection} input collection * * @example * function scale( value, index, collection ) { * console.log( '%s: %d', index, value ); * return value * index; * } * * var arr = [ 1, 2, 3, 4 ]; * * var out = inmapRight( arr, scale ); * // returns [ 0, 2, 6, 12 ] * * var bool = ( out === arr ); * // returns true */ function inmapRight( collection, fcn, thisArg ) { var len; var v; var i; if ( !isCollection( collection ) ) { throw new TypeError( 'invalid argument. First argument must be a collection. Value: `'+collection+'`.' ); } if ( !isFunction( fcn ) ) { throw new TypeError( 'invalid argument. Second argument must be a function. Value: `'+fcn+'`.' ); } len = collection.length; for ( i = len-1; i >= 0; i-- ) { v = fcn.call( thisArg, collection[ i ], i, collection ); // Account for dynamically resizing a collection... if ( len !== collection.length ) { i += ( collection.length - len ); len = collection.length; } if ( i >= 0 && i < len ) { collection[ i ] = v; } } return collection; } // EXPORTS // module.exports = inmapRight;