omit_by.js (1900B)
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 objectKeys = require( './../../keys' ); 24 var isFunction = require( '@stdlib/assert/is-function' ); 25 26 27 // MAIN // 28 29 /** 30 * Returns a partial object copy excluding properties for which a predicate returns a truthy value. 31 * 32 * @param {Object} obj - source object 33 * @param {Function} predicate - predicate function 34 * @throws {TypeError} first argument must be an object 35 * @throws {TypeError} second argument must be a function 36 * @returns {Object} new object 37 * 38 * @example 39 * function predicate( key, value ) { 40 * return ( value > 1 ); 41 * } 42 * 43 * var obj1 = { 44 * 'a': 1, 45 * 'b': 2 46 * }; 47 * 48 * var obj2 = omitBy( obj1, predicate ); 49 * // returns { 'a': 1 } 50 */ 51 function omitBy( obj, predicate ) { 52 var keys; 53 var out; 54 var key; 55 var i; 56 if ( typeof obj !== 'object' || obj === null ) { 57 throw new TypeError( 'invalid argument. First argument must be an object. Value: `'+obj+'`.' ); 58 } 59 if ( !isFunction( predicate ) ) { 60 throw new TypeError( 'invalid argument. Second argument must be a function. Value: `'+predicate+'`.' ); 61 } 62 out = {}; 63 keys = objectKeys( obj ); 64 for ( i = 0; i < keys.length; i++ ) { 65 key = keys[ i ]; 66 if ( !predicate( key, obj[ key ] ) ) { 67 out[ key ] = obj[ key ]; 68 } 69 } 70 return out; 71 } 72 73 74 // EXPORTS // 75 76 module.exports = omitBy;