time-to-botec

Benchmark sampling in different programming languages
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try_then_async.js (3220B)

      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 
     25 
     26 // MAIN //
     27 
     28 /**
     29 * If a function does not return an error, invokes a callback with the function result; otherwise, invokes a second function `y`.
     30 *
     31 * @param {Function} x - function to invoke
     32 * @param {Function} y - function to invoke if `x` returns an error
     33 * @param {Function} done - callback to invoke upon completion
     34 * @throws {TypeError} first argument must be a function
     35 * @throws {TypeError} second argument must be a function
     36 * @throws {TypeError} last argument must be a function
     37 *
     38 * @example
     39 * var randu = require( '@stdlib/random/base/randu' );
     40 *
     41 * function x( clbk ) {
     42 *     setTimeout( onTimeout, 0 );
     43 *     function onTimeout() {
     44 *         if ( randu() > 0.5 ) {
     45 *             return clbk( null, 1.0 );
     46 *         }
     47 *         clbk( new Error( 'beep' ) );
     48 *     }
     49 * }
     50 *
     51 * function y( clbk ) {
     52 *     setTimeout( onTimeout, 0 );
     53 *     function onTimeout() {
     54 *         clbk( null, -1.0 );
     55 *     }
     56 * }
     57 *
     58 * function done( error, result ) {
     59 *     if ( error ) {
     60 *         throw error;
     61 *     }
     62 *     console.log( result );
     63 * }
     64 *
     65 * trythenAsync( x, y, done );
     66 */
     67 function trythenAsync( x, y, done ) {
     68 	if ( !isFunction( x ) ) {
     69 		throw new TypeError( 'invalid argument. First argument must be a function. Value: `'+x+'`.' );
     70 	}
     71 	if ( !isFunction( y ) ) {
     72 		throw new TypeError( 'invalid argument. Second argument must be a function. Value: `'+y+'`.' );
     73 	}
     74 	if ( !isFunction( done ) ) {
     75 		throw new TypeError( 'invalid argument. Last argument must be a function. Value: `'+done+'`.' );
     76 	}
     77 	x( clbk1 );
     78 
     79 	/**
     80 	* Callback invoked by `x`.
     81 	*
     82 	* @private
     83 	* @param {(Error|null)} error - error object
     84 	* @param {...*} args - function results
     85 	* @returns {void}
     86 	*/
     87 	function clbk1( error ) {
     88 		var nargs;
     89 		var args;
     90 		var i;
     91 		if ( error ) {
     92 			if ( y.length === 1 ) {
     93 				return y( clbk2 );
     94 			}
     95 			return y( error, clbk2 );
     96 		}
     97 		nargs = arguments.length;
     98 		args = new Array( nargs );
     99 		args[ 0 ] = null;
    100 		for ( i = 1; i < nargs; i++ ) {
    101 			args[ i ] = arguments[ i ];
    102 		}
    103 		return done.apply( null, args );
    104 	}
    105 
    106 	/**
    107 	* Callback invoked by `y`.
    108 	*
    109 	* @private
    110 	* @param {(Error|null)} error - error object
    111 	* @param {...*} args - function results
    112 	* @returns {void}
    113 	*/
    114 	function clbk2( error ) {
    115 		var nargs;
    116 		var args;
    117 		var i;
    118 		if ( error ) {
    119 			return done( error );
    120 		}
    121 		nargs = arguments.length;
    122 		args = new Array( nargs );
    123 		args[ 0 ] = null;
    124 		for ( i = 1; i < nargs; i++ ) {
    125 			args[ i ] = arguments[ i ];
    126 		}
    127 		return done.apply( null, args );
    128 	}
    129 }
    130 
    131 
    132 // EXPORTS //
    133 
    134 module.exports = trythenAsync;