main.js (1392B)
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 PINF = require( '@stdlib/constants/float64/pinf' ); 24 var NINF = require( '@stdlib/constants/float64/ninf' ); 25 26 27 // MAIN // 28 29 /** 30 * Tests if a double-precision floating-point numeric value is finite. 31 * 32 * @param {number} x - value to test 33 * @returns {boolean} boolean indicating whether the value is finite 34 * 35 * @example 36 * var bool = isfinite( 5.0 ); 37 * // returns true 38 * 39 * @example 40 * var bool = isfinite( -2.0e64 ); 41 * // returns true 42 * 43 * @example 44 * var bool = isfinite( Infinity ); 45 * // returns false 46 * 47 * @example 48 * var bool = isfinite( -Infinity ); 49 * // returns false 50 */ 51 function isfinite( x ) { 52 return ( 53 // NaN check (x !== x ): 54 x === x && 55 56 // +-infinity check: 57 x > NINF && 58 x < PINF 59 ); 60 } 61 62 63 // EXPORTS // 64 65 module.exports = isfinite;