primitive.js (1284B)
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 isNumber = require( './../../is-number' ).isPrimitive; 24 var NINF = require( '@stdlib/constants/float64/ninf' ); 25 26 27 // MAIN // 28 29 /** 30 * Tests if a value is a number primitive equal to negative zero. 31 * 32 * @param {*} value - value to test 33 * @returns {boolean} boolean indicating if a value is a number primitive equal to negative zero 34 * 35 * @example 36 * var bool = isNegativeZero( -0.0 ); 37 * // returns true 38 * 39 * @example 40 * var bool = isNegativeZero( new Number( -0.0 ) ); 41 * // returns false 42 */ 43 function isNegativeZero( value ) { 44 return ( 45 isNumber( value ) && 46 ( 1.0 / value ) === NINF 47 ); 48 } 49 50 51 // EXPORTS // 52 53 module.exports = isNegativeZero;