time-to-botec

Benchmark sampling in different programming languages
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main.js (4362B)

      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 isFunction = require( '@stdlib/assert/is-function' );
     25 var isIteratorLike = require( '@stdlib/assert/is-iterator-like' );
     26 var isNumber = require( '@stdlib/assert/is-number' ).isPrimitive;
     27 var hasOwnProp = require( '@stdlib/assert/has-own-property' );
     28 var iteratorSymbol = require( '@stdlib/symbol/iterator' );
     29 var validate = require( './validate.js' );
     30 
     31 
     32 // MAIN //
     33 
     34 /**
     35 * Returns an iterator which invokes a unary function accepting a single numeric argument for each iterated value.
     36 *
     37 * ## Notes
     38 *
     39 * -   When invoked, the input function is provided one argument:
     40 *
     41 *     -   `value`: iterated value
     42 *
     43 * -   If an environment supports `Symbol.iterator` **and** a provided iterator is iterable, the returned iterator is iterable.
     44 *
     45 * @param {Iterator} iterator - input iterator
     46 * @param {Function} fcn - function to invoke
     47 * @param {Options} [options] - options
     48 * @param {*} [options.invalid=NaN] - return value when an input iterator yields a non-numeric value
     49 * @throws {TypeError} first argument must be an iterator protocol-compliant object
     50 * @throws {TypeError} second argument must be a function
     51 * @throws {TypeError} options argument must be an object
     52 * @throws {TypeError} must provide valid options
     53 * @returns {Iterator} iterator
     54 *
     55 * @example
     56 * var randu = require( '@stdlib/random/iter/randu' );
     57 * var sin = require( '@stdlib/math/base/special/sin' );
     58 *
     59 * var iter = iterMap( randu(), sin );
     60 *
     61 * var r = iter.next().value;
     62 * // returns <number>
     63 *
     64 * r = iter.next().value;
     65 * // returns <number>
     66 *
     67 * r = iter.next().value;
     68 * // returns <number>
     69 *
     70 * // ...
     71 */
     72 function iterMap( iterator, fcn, options ) {
     73 	var opts;
     74 	var iter;
     75 	var err;
     76 	var FLG;
     77 	if ( !isIteratorLike( iterator ) ) {
     78 		throw new TypeError( 'invalid argument. First argument must be an iterator protocol-compliant object. Value: `' + iterator + '`.' );
     79 	}
     80 	if ( !isFunction( fcn ) ) {
     81 		throw new TypeError( 'invalid argument. Second argument must be a function. Value: `' + fcn + '`.' );
     82 	}
     83 	opts = {
     84 		'invalid': NaN
     85 	};
     86 	if ( arguments.length > 2 ) {
     87 		err = validate( opts, options );
     88 		if ( err ) {
     89 			throw err;
     90 		}
     91 	}
     92 	// Create an iterator protocol-compliant object:
     93 	iter = {};
     94 	setReadOnly( iter, 'next', next );
     95 	setReadOnly( iter, 'return', end );
     96 
     97 	// If an environment supports `Symbol.iterator` and the provided iterator is iterable, make the iterator iterable:
     98 	if ( iteratorSymbol && isFunction( iterator[ iteratorSymbol ] ) ) {
     99 		setReadOnly( iter, iteratorSymbol, factory );
    100 	}
    101 	return iter;
    102 
    103 	/**
    104 	* Returns an iterator protocol-compliant object containing the next iterated value.
    105 	*
    106 	* @private
    107 	* @returns {Object} iterator protocol-compliant object
    108 	*/
    109 	function next() {
    110 		var out;
    111 		var v;
    112 		if ( FLG ) {
    113 			return {
    114 				'done': true
    115 			};
    116 		}
    117 		v = iterator.next();
    118 		if ( v.done ) {
    119 			FLG = true;
    120 			out = {};
    121 			if ( hasOwnProp( v, 'value' ) ) {
    122 				out.value = ( isNumber( v.value ) ) ? fcn( v.value ) : opts.invalid; // eslint-disable-line max-len
    123 			}
    124 			out.done = true;
    125 			return out;
    126 		}
    127 		return {
    128 			'value': ( isNumber( v.value ) ) ? fcn( v.value ) : opts.invalid,
    129 			'done': false
    130 		};
    131 	}
    132 
    133 	/**
    134 	* Finishes an iterator.
    135 	*
    136 	* @private
    137 	* @param {*} [value] - value to return
    138 	* @returns {Object} iterator protocol-compliant object
    139 	*/
    140 	function end( value ) {
    141 		FLG = true;
    142 		if ( arguments.length ) {
    143 			return {
    144 				'value': value,
    145 				'done': true
    146 			};
    147 		}
    148 		return {
    149 			'done': true
    150 		};
    151 	}
    152 
    153 	/**
    154 	* Returns a new iterator.
    155 	*
    156 	* @private
    157 	* @returns {Iterator} iterator
    158 	*/
    159 	function factory() {
    160 		return iterMap( iterator[ iteratorSymbol ](), fcn, opts );
    161 	}
    162 }
    163 
    164 
    165 // EXPORTS //
    166 
    167 module.exports = iterMap;