time-to-botec

Benchmark sampling in different programming languages
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main.js (3210B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2019 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 isIteratorLike = require( '@stdlib/assert/is-iterator-like' );
     25 var isFunction = require( '@stdlib/assert/is-function' );
     26 var hasOwnProp = require( '@stdlib/assert/has-own-property' );
     27 var iteratorSymbol = require( '@stdlib/symbol/iterator' );
     28 var incrmean = require( './../../../incr/mean' );
     29 
     30 
     31 // MAIN //
     32 
     33 /**
     34 * Returns an iterator which iteratively computes a cumulative arithmetic mean.
     35 *
     36 * @param {Iterator} iterator - input iterator
     37 * @throws {TypeError} must provide an iterator
     38 * @returns {Iterator} iterator
     39 *
     40 * @example
     41 * var runif = require( '@stdlib/random/iter/uniform' );
     42 *
     43 * var rand = runif( -10.0, 10.0, {
     44 *     'iter': 100
     45 * });
     46 *
     47 * var it = itercumean( rand );
     48 *
     49 * var v = it.next().value;
     50 * // returns <number>
     51 *
     52 * v = it.next().value;
     53 * // returns <number>
     54 *
     55 * v = it.next().value;
     56 * // returns <number>
     57 *
     58 * // ...
     59 */
     60 function itercumean( iterator ) {
     61 	var iter;
     62 	var FLG;
     63 	var acc;
     64 	if ( !isIteratorLike( iterator ) ) {
     65 		throw new TypeError( 'invalid argument. Must provide an iterator. Value: `' + iterator + '`.' );
     66 	}
     67 	acc = incrmean();
     68 
     69 	// Create an iterator protocol-compliant object:
     70 	iter = {};
     71 	setReadOnly( iter, 'next', next );
     72 	setReadOnly( iter, 'return', end );
     73 
     74 	// If an environment supports `Symbol.iterator`, make the iterator iterable:
     75 	if ( iteratorSymbol && isFunction( iterator[ iteratorSymbol ] ) ) {
     76 		setReadOnly( iter, iteratorSymbol, factory );
     77 	}
     78 	return iter;
     79 
     80 	/**
     81 	* Returns an iterator protocol-compliant object containing the next iterated value.
     82 	*
     83 	* @private
     84 	* @returns {Object} iterator protocol-compliant object
     85 	*/
     86 	function next() {
     87 		var out;
     88 		var v;
     89 		if ( FLG ) {
     90 			return {
     91 				'done': true
     92 			};
     93 		}
     94 		out = {};
     95 		v = iterator.next();
     96 		if ( typeof v.value === 'number' ) {
     97 			out.value = acc( v.value );
     98 		} else if ( hasOwnProp( v, 'value' ) ) {
     99 			out.value = acc( NaN );
    100 		}
    101 		if ( v.done ) {
    102 			FLG = true;
    103 			out.done = true;
    104 		} else {
    105 			out.done = false;
    106 		}
    107 		return out;
    108 	}
    109 
    110 	/**
    111 	* Finishes an iterator.
    112 	*
    113 	* @private
    114 	* @param {*} [value] - value to return
    115 	* @returns {Object} iterator protocol-compliant object
    116 	*/
    117 	function end( value ) {
    118 		FLG = true;
    119 		if ( arguments.length ) {
    120 			return {
    121 				'value': value,
    122 				'done': true
    123 			};
    124 		}
    125 		return {
    126 			'done': true
    127 		};
    128 	}
    129 
    130 	/**
    131 	* Returns a new iterator.
    132 	*
    133 	* @private
    134 	* @returns {Iterator} iterator
    135 	*/
    136 	function factory() {
    137 		return itercumean( iterator[ iteratorSymbol ]() );
    138 	}
    139 }
    140 
    141 
    142 // EXPORTS //
    143 
    144 module.exports = itercumean;