every_by_right.js (2500B)
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 * Tests whether all elements in a collection pass a test implemented by a predicate function, iterating from right to left. 31 * 32 * ## Notes 33 * 34 * - For dynamic array resizing, the only behavior made intentionally consistent with `every` (iterating from left to right) is when elements are pushed onto the beginning (end) of an array. In other words, for `every()`, `[].push()` behavior is consistent with `everyByRight()` `[].unshift()` behavior. 35 * 36 * @param {Collection} collection - input collection 37 * @param {Function} predicate - test function 38 * @param {*} [thisArg] - execution context 39 * @throws {TypeError} first argument must be a collection 40 * @throws {TypeError} second argument must be a function 41 * @returns {boolean} boolean indicating whether all elements pass a test 42 * 43 * @example 44 * function isPositive( v ) { 45 * return ( v > 0 ); 46 * } 47 * 48 * var arr = [ 1, 2, 3, 4 ]; 49 * 50 * var bool = everyByRight( arr, isPositive ); 51 * // returns true 52 */ 53 function everyByRight( collection, predicate, thisArg ) { 54 var out; 55 var len; 56 var i; 57 if ( !isCollection( collection ) ) { 58 throw new TypeError( 'invalid argument. First argument must be a collection. Value: `'+collection+'`.' ); 59 } 60 if ( !isFunction( predicate ) ) { 61 throw new TypeError( 'invalid argument. Second argument must be a function. Value: `'+predicate+'`.' ); 62 } 63 len = collection.length; 64 for ( i = len-1; i >= 0; i-- ) { 65 out = predicate.call( thisArg, collection[ i ], i, collection ); 66 if ( !out ) { 67 return false; 68 } 69 // Account for dynamically resizing a collection... 70 if ( len !== collection.length ) { 71 i += ( collection.length - len ); 72 len = collection.length; 73 } 74 } 75 return true; 76 } 77 78 79 // EXPORTS // 80 81 module.exports = everyByRight;