time-to-botec

Benchmark sampling in different programming languages
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factory.js (4501B)

      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 isFunction = require( '@stdlib/assert/is-function' );
     24 var PINF = require( '@stdlib/constants/float64/pinf' );
     25 var validate = require( './validate.js' );
     26 var limit = require( './limit.js' );
     27 
     28 
     29 // MAIN //
     30 
     31 /**
     32 * Returns a function to map values from one object to a new object having the same keys.
     33 *
     34 * ## Notes
     35 *
     36 * -   If a provided function calls the provided callback with a truthy error argument, the function suspends execution and immediately calls the `done` callback for subsequent error handling.
     37 * -   This function does **not** guarantee that execution is asynchronous. To do so, wrap the `done` callback in a function which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).
     38 * -   Iteration and insertion order are **not** guaranteed.
     39 * -   The function only operates on own properties, not inherited properties.
     40 *
     41 *
     42 * @param {Options} [options] - function options
     43 * @param {*} [options.thisArg] - execution context
     44 * @param {PositiveInteger} [options.limit] - maximum number of pending invocations at any one time
     45 * @param {boolean} [options.series=false] - boolean indicating whether to wait for a previous invocation to complete before invoking a provided function for the next own property
     46 * @param {Function} transform - transform function
     47 * @throws {TypeError} options argument must be an object
     48 * @throws {TypeError} must provide valid options
     49 * @throws {TypeError} last argument must be a function
     50 * @returns {Function} function which maps values from one object to a new object having the same keys
     51 *
     52 * @example
     53 * var stat = require( 'fs' ).stat;
     54 *
     55 * function getStats( file, next ) {
     56 *     stat( file, onStats );
     57 *
     58 *     function onStats( error, data ) {
     59 *         if ( error ) {
     60 *             return next( error );
     61 *         }
     62 *         next( null, data );
     63 *     }
     64 * }
     65 *
     66 * var opts = {
     67 *     'series': true
     68 * };
     69 *
     70 * // Create a reusable function:
     71 * var mapValuesAsync = factory( opts, getStats );
     72 *
     73 * // Create a dictionary of file names:
     74 * var files = {
     75 *     'file1': './beep.js',
     76 *     'file2': './boop.js'
     77 * };
     78 *
     79 * // Define a callback which handles errors:
     80 * function done( error, out ) {
     81 *     if ( error ) {
     82 *         throw error;
     83 *     }
     84 *     console.log( out );
     85 * }
     86 *
     87 * // Process each file in `files`:
     88 * mapValuesAsync( files, done );
     89 */
     90 function factory( options, transform ) {
     91 	var opts;
     92 	var err;
     93 	var f;
     94 
     95 	opts = {};
     96 	if ( arguments.length > 1 ) {
     97 		err = validate( opts, options );
     98 		if ( err ) {
     99 			throw err;
    100 		}
    101 		f = transform;
    102 	} else {
    103 		f = options;
    104 	}
    105 	if ( !isFunction( f ) ) {
    106 		throw new TypeError( 'invalid argument. Last argument must be a function. Value: `'+f+'`.' );
    107 	}
    108 	if ( opts.series ) {
    109 		opts.limit = 1;
    110 	} else if ( !opts.limit ) {
    111 		opts.limit = PINF;
    112 	}
    113 	return mapValuesAsync;
    114 
    115 	/**
    116 	* Maps values from one object to a new object having the same keys.
    117 	*
    118 	* @private
    119 	* @param {Object} obj - source object
    120 	* @param {Callback} done - function to invoke upon completion
    121 	* @throws {TypeError} first argument must be an object
    122 	* @throws {TypeError} last argument must be a function
    123 	* @returns {void}
    124 	*/
    125 	function mapValuesAsync( obj, done ) {
    126 		if ( typeof obj !== 'object' || obj === null ) {
    127 			throw new TypeError( 'invalid argument. First argument must be an object. Value: `'+obj+'.`' );
    128 		}
    129 		if ( !isFunction( done ) ) {
    130 			throw new TypeError( 'invalid argument. Last argument must be a function. Value: `'+done+'`.' );
    131 		}
    132 		return limit( obj, opts, f, clbk );
    133 
    134 		/**
    135 		* Callback invoked upon completion.
    136 		*
    137 		* @private
    138 		* @param {*} [error] - error
    139 		* @param {Object} [out] - output object
    140 		* @returns {void}
    141 		*/
    142 		function clbk( error, out ) {
    143 			if ( error ) {
    144 				return done( error );
    145 			}
    146 			done( null, out );
    147 		}
    148 	}
    149 }
    150 
    151 
    152 // EXPORTS //
    153 
    154 module.exports = factory;