main.js (2950B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2020 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 setReadOnly = require( '@stdlib/utils/define-nonenumerable-read-only-property' ); 24 var iteratorSymbol = require( '@stdlib/symbol/iterator' ); 25 var validate = require( './validate.js' ); 26 27 28 // VARIABLES // 29 30 var MAX_ITER = 1552; // floor((FLOAT64_MAX_SAFE_INTEGER)^0.2) 31 32 33 // MAIN // 34 35 /** 36 * Returns an iterator which generates a sequence of fifth powers. 37 * 38 * ## Notes 39 * 40 * - If an environment supports `Symbol.iterator`, the returned iterator is iterable. 41 * 42 * @param {Options} [options] - function options 43 * @param {NonNegativeInteger} [options.iter=9741] - number of iterations 44 * @throws {TypeError} options argument must be an object 45 * @throws {TypeError} must provide valid options 46 * @returns {Iterator} iterator 47 * 48 * @example 49 * var iter = iterFifthPowersSeq(); 50 * 51 * var v = iter.next().value; 52 * // returns 0 53 * 54 * v = iter.next().value; 55 * // returns 1 56 * 57 * v = iter.next().value; 58 * // returns 32 59 * 60 * // ... 61 */ 62 function iterFifthPowersSeq( options ) { 63 var opts; 64 var iter; 65 var FLG; 66 var err; 67 var i; 68 69 opts = { 70 'iter': MAX_ITER 71 }; 72 if ( arguments.length ) { 73 err = validate( opts, options ); 74 if ( err ) { 75 throw err; 76 } 77 } 78 i = -1; 79 80 // Create an iterator protocol-compliant object: 81 iter = {}; 82 setReadOnly( iter, 'next', next ); 83 setReadOnly( iter, 'return', end ); 84 85 // If an environment supports `Symbol.iterator`, make the iterator iterable: 86 if ( iteratorSymbol ) { 87 setReadOnly( iter, iteratorSymbol, factory ); 88 } 89 return iter; 90 91 /** 92 * Returns an iterator protocol-compliant object containing the next iterated value. 93 * 94 * @private 95 * @returns {Object} iterator protocol-compliant object 96 */ 97 function next() { 98 var v; 99 i += 1; 100 if ( FLG || i >= opts.iter ) { 101 return { 102 'done': true 103 }; 104 } 105 v = i * i; 106 return { 107 'value': v * v * i, 108 'done': false 109 }; 110 } 111 112 /** 113 * Finishes an iterator. 114 * 115 * @private 116 * @param {*} [value] - value to return 117 * @returns {Object} iterator protocol-compliant object 118 */ 119 function end( value ) { 120 FLG = true; 121 if ( arguments.length ) { 122 return { 123 'value': value, 124 'done': true 125 }; 126 } 127 return { 128 'done': true 129 }; 130 } 131 132 /** 133 * Returns a new iterator. 134 * 135 * @private 136 * @returns {Iterator} iterator 137 */ 138 function factory() { 139 return iterFifthPowersSeq( opts ); 140 } 141 } 142 143 144 // EXPORTS // 145 146 module.exports = iterFifthPowersSeq;