time-to-botec

Benchmark sampling in different programming languages
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do_until_each_right.js (3339B)

      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 * Until a test condition is true, 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 `doUntilEach` (iterating from left to right) is when elements are pushed onto the beginning (end) of an array. In other words, for `doUntilEach()`, `[].push()` behavior is consistent with `doUntilEachRight()` `[].unshift()` behavior.
     35 * -   The condition is evaluated **after** executing the function to invoke; thus, the provided function **always** executes at least once.
     36 * -   If provided an empty collection, the function invokes the provided function with the collection index set to `undefined`.
     37 *
     38 *
     39 * @param {Collection} collection - input collection
     40 * @param {Function} fcn - function to invoke
     41 * @param {Function} predicate - function which indicates whether to stop iterating over a collection
     42 * @param {*} [thisArg] - execution context for the applied function
     43 * @throws {TypeError} first argument must be a collection
     44 * @throws {TypeError} second argument must be a function
     45 * @throws {TypeError} third argument must be a function
     46 * @returns {Collection} input collection
     47 *
     48 * @example
     49 * function predicate( v, index, collection ) {
     50 *     return ( v !== v );
     51 * }
     52 *
     53 * function log( v, index, collection ) {
     54 *     console.log( '%s: %d', index, v );
     55 * }
     56 *
     57 * var arr = [ 1, NaN, 2, 3, 4, 5 ];
     58 *
     59 * doUntilEachRight( arr, log, predicate );
     60 */
     61 function doUntilEachRight( collection, fcn, predicate, thisArg ) {
     62 	var len;
     63 	var i;
     64 	if ( !isCollection( collection ) ) {
     65 		throw new TypeError( 'invalid argument. First argument must be a collection. Value: `'+collection+'`.' );
     66 	}
     67 	if ( !isFunction( fcn ) ) {
     68 		throw new TypeError( 'invalid argument. Second argument must be a function. Value: `'+fcn+'`.' );
     69 	}
     70 	if ( !isFunction( predicate ) ) {
     71 		throw new TypeError( 'invalid argument. Third argument must be a function. Value: `'+predicate+'`.' );
     72 	}
     73 	len = collection.length;
     74 	if ( len === 0 ) {
     75 		fcn.call( thisArg, void 0, void 0, collection );
     76 		len = collection.length;
     77 		if ( len === 0 ) {
     78 			return collection;
     79 		}
     80 	}
     81 	i = len - 1;
     82 	do {
     83 		fcn.call( thisArg, collection[ i ], i, collection );
     84 
     85 		// Account for dynamically resizing a collection...
     86 		if ( len !== collection.length ) {
     87 			i += ( collection.length - len );
     88 			len = collection.length;
     89 		}
     90 		i -= 1;
     91 	} while (
     92 		i >= 0 &&
     93 		!predicate( collection[ i+1 ], i+1, collection )
     94 	);
     95 	return collection;
     96 }
     97 
     98 
     99 // EXPORTS //
    100 
    101 module.exports = doUntilEachRight;