time-to-botec

Benchmark sampling in different programming languages
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pick.js (2106B)

      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 isString = require( '@stdlib/assert/is-string' ).isPrimitive;
     24 var isStringArray = require( '@stdlib/assert/is-string-array' ).primitives;
     25 var hasOwnProp = require( '@stdlib/assert/has-own-property' );
     26 
     27 
     28 // MAIN //
     29 
     30 /**
     31 * Returns a partial object copy containing only specified keys. If a key does not exist as an own property in a source object, the key is ignored.
     32 *
     33 * @param {Object} obj - source object
     34 * @param {(string|StringArray)} keys - keys to copy
     35 * @throws {TypeError} first argument must be an object
     36 * @throws {TypeError} second argument must be either a string or an array of strings
     37 * @returns {Object} new object
     38 *
     39 * @example
     40 * var obj1 = {
     41 *     'a': 1,
     42 *     'b': 2
     43 * };
     44 *
     45 * var obj2 = pick( obj1, 'b' );
     46 * // returns { 'b': 2 }
     47 */
     48 function pick( obj, keys ) {
     49 	var out;
     50 	var key;
     51 	var i;
     52 	if ( typeof obj !== 'object' || obj === null ) {
     53 		throw new TypeError( 'invalid argument. First argument must be an object. Value: `'+obj+'`.' );
     54 	}
     55 	out = {};
     56 	if ( isString( keys ) ) {
     57 		if ( hasOwnProp( obj, keys ) ) {
     58 			out[ keys ] = obj[ keys ];
     59 		}
     60 		return out;
     61 	}
     62 	if ( isStringArray( keys ) ) {
     63 		for ( i = 0; i < keys.length; i++ ) {
     64 			key = keys[ i ];
     65 			if ( hasOwnProp( obj, key ) ) {
     66 				out[ key ] = obj[ key ];
     67 			}
     68 		}
     69 		return out;
     70 	}
     71 	throw new TypeError( 'invalid argument. Second argument must be either a string primitive or an array of string primitives. Value: `'+keys+'`.' );
     72 }
     73 
     74 
     75 // EXPORTS //
     76 
     77 module.exports = pick;