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• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

Uint8Array() constructor creates a typed array of 8-bit unsigned integers. The contents are initialized to 0 . Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).

句法

new Uint8Array(); // new in ES2017
new Uint8Array(length);
new Uint8Array(typedArray);
new Uint8Array(object);
new Uint8Array(buffer [, byteOffset [, length]]);
					

参数

length

When called with a length argument, an internal array buffer is created in memory, of size length multiplied by BYTES_PER_ELEMENT bytes, containing zeros.

typedArray

When called with a typedArray argument, which can be an object of any of the typed array types (such as Int32Array ), the typedArray gets copied into a new typed array. Each value in typedArray is converted to the corresponding type of the constructor before being copied into the new array. The length of the new typed array will be same as the length of the typedArray 自变量。

object

When called with an object argument, a new typed array is created as if by the TypedArray .from() 方法。

buffer , byteOffset , length

When called with a buffer , and optionally a byteOffset 和 length argument, a new typed array view is created that views the specified ArrayBuffer 。 byteOffset and length parameters specify the memory range that will be exposed by the typed array view.  If both are omitted, all of buffer is viewed; if only length is omitted, the remainder of buffer is viewed.

范例

Different ways to create a Uint8Array

// From a length
var uint8 = new Uint8Array(2);
uint8[0] = 42;
console.log(uint8[0]); // 42
console.log(uint8.length); // 2
console.log(uint8.BYTES_PER_ELEMENT); // 1
// From an array
var arr = new Uint8Array([21,31]);
console.log(arr[1]); // 31
// From another TypedArray
var x = new Uint8Array([21, 31]);
var y = new Uint8Array(x);
console.log(y[0]); // 21
// From an ArrayBuffer
var buffer = new ArrayBuffer(8);
var z = new Uint8Array(buffer, 1, 4);
// From an iterable
var iterable = function*(){ yield* [1,2,3]; }();
var uint8 = new Uint8Array(iterable);
// Uint8Array[1, 2, 3]
					

规范

规范
ECMAScript (ECMA-262) The definition of 'TypedArray constructors' in that specification.

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
Uint8Array() 构造函数	Chrome 7	Edge 12	Firefox 4	IE 10	Opera 11.6	Safari 5.1	WebView Android 4	Chrome Android 18	Firefox Android 4	Opera Android 12	Safari iOS 4.2	Samsung Internet Android 1.0	nodejs 0.10
Constructor without arguments	Chrome 7	Edge 12	Firefox 55	IE 10	Opera 11.6	Safari 5.1	WebView Android ≤37	Chrome Android 18	Firefox Android 55	Opera Android 12	Safari iOS 5	Samsung Internet Android 1.0	nodejs 0.10
new Uint8Array(iterable)	Chrome 39	Edge 14	Firefox 52	IE No	Opera 26	Safari 10	WebView Android 39	Chrome Android 39	Firefox Android 52	Opera Android 26	Safari iOS 10	Samsung Internet Android 4.0	nodejs 4.0.0
Uint8Array() without new throws	Chrome 7	Edge 14	Firefox 44	IE No	Opera 15	Safari 5.1	WebView Android ≤37	Chrome Android 18	Firefox Android 44	Opera Android 14	Safari iOS 5	Samsung Internet Android 1.0	nodejs 0.12

图例

完整支持

完整支持

不支持

不支持

Compatibility notes

Starting with ECMAScript 2015, Uint8Array constructors require to be constructed with a new operator. Calling a Uint8Array constructor as a function without new , will throw a TypeError from now on.

var dv = Uint8Array([1, 2, 3]);
// TypeError: calling a builtin Uint8Array constructor
// without new is forbidden
					

var dv = new Uint8Array([1, 2, 3]);
					

另请参阅

• JavaScript 类型数组
• ArrayBuffer
• DataView

元数据

• 最后修改： May 7, 2020

相关话题

1. 标准内置对象
2. TypedArray
3. 特性
   1. TypedArray.BYTES_PER_ELEMENT
   2. TypedArray.name
   3. TypedArray.prototype.buffer
   4. TypedArray.prototype.byteLength
   5. TypedArray.prototype.byteOffset
   6. TypedArray.prototype.length
   7. get TypedArray[@@species]
4. 方法
   1. TypedArray.from()
   2. TypedArray.of()
   3. TypedArray.prototype.copyWithin()
   4. TypedArray.prototype.entries()
   5. TypedArray.prototype.every()
   6. TypedArray.prototype.fill()
   7. TypedArray.prototype.filter()
   8. TypedArray.prototype.find()
   9. TypedArray.prototype.findIndex()
   10. TypedArray.prototype.forEach()
   11. TypedArray.prototype.includes()
   12. TypedArray.prototype.indexOf()
   13. TypedArray.prototype.join()
   14. TypedArray.prototype.keys()
   15. TypedArray.prototype.lastIndexOf()
   16. TypedArray.prototype.map()
   17. TypedArray.prototype.reduce()
   18. TypedArray.prototype.reduceRight()
   19. TypedArray.prototype.reverse()
   20. TypedArray.prototype.set()
   21. TypedArray.prototype.slice()
   22. TypedArray.prototype.some()
   23. TypedArray.prototype.sort()
   24. TypedArray.prototype.subarray()
   25. TypedArray.prototype.toLocaleString()
   26. TypedArray.prototype.toString()
   27. TypedArray.prototype.values()
   28. TypedArray.prototype[@@iterator]()
5. 相关页面：
6. Int8Array
7. Uint8Array
8. Uint8ClampedArray
9. Int16Array
10. Uint16Array
11. Int32Array
12. Uint32Array
13. Float32Array
14. Float64Array
15. BigInt64Array
16. BigUint64Array
17. 继承：
18. Function
19. 特性
    1. Function.arguments
    2. Function.caller
    3. Function.displayName
    4. Function.length
    5. Function.name
20. 方法
    1. Function.prototype.apply()
    2. Function.prototype.bind()
    3. Function.prototype.call()
    4. Function.prototype.toSource()
    5. Function.prototype.toString()
21. Object
22. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
23. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()