main.js (1691B)
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 isUint8Array = require( './../../is-uint8array' ); 24 var UINT8_MAX = require( '@stdlib/constants/uint8/max' ); 25 var GlobalUint8Array = require( './uint8array.js' ); 26 27 28 // MAIN // 29 30 /** 31 * Tests for native `Uint8Array` support. 32 * 33 * @returns {boolean} boolean indicating if an environment has `Uint8Array` support 34 * 35 * @example 36 * var bool = hasUint8ArraySupport(); 37 * // returns <boolean> 38 */ 39 function hasUint8ArraySupport() { 40 var bool; 41 var arr; 42 43 if ( typeof GlobalUint8Array !== 'function' ) { 44 return false; 45 } 46 // Test basic support... 47 try { 48 arr = [ 1, 3.14, -3.14, UINT8_MAX+1, UINT8_MAX+2 ]; 49 arr = new GlobalUint8Array( arr ); 50 bool = ( 51 isUint8Array( arr ) && 52 arr[ 0 ] === 1 && 53 arr[ 1 ] === 3 && // truncation 54 arr[ 2 ] === UINT8_MAX-2 && // truncation and wrap around 55 arr[ 3 ] === 0 && // wrap around 56 arr[ 4 ] === 1 // wrap around 57 ); 58 } catch ( err ) { // eslint-disable-line no-unused-vars 59 bool = false; 60 } 61 return bool; 62 } 63 64 65 // EXPORTS // 66 67 module.exports = hasUint8ArraySupport;