ArrayBuffer

語法

new ArrayBuffer(length)

參數

length

要建立的緩衝陣列大小，以位元組（byte）計算。

回傳值

為一個新建立的指定大小 ArrayBuffer 物件，其內容皆初始化為 0。

Exceptions

A RangeError is thrown if the length is larger than Number.MAX_SAFE_INTEGER (>= 2 ** 53) or negative.

說明

The ArrayBuffer constructor creates a new ArrayBuffer of the given length in bytes.

從既有的資料取得 ArrayBuffer

• From a Base64 string
• 從本地端檔案

屬性

ArrayBuffer.length

The ArrayBuffer constructor's length property whose value is 1.

ArrayBuffer[Symbol.species]

The constructor function that is used to create derived objects.

ArrayBuffer.prototype

Allows the addition of properties to all ArrayBuffer objects.

方法

ArrayBuffer.isView(arg)

Returns true if arg is one of the ArrayBuffer views, such as typed array objects or a DataView. Returns false otherwise.

ArrayBuffer.transfer(oldBuffer [, newByteLength]) 實驗性質

Returns a new ArrayBuffer whose contents are taken from the oldBuffer's data and then is either truncated or zero-extended by newByteLength.

ArrayBuffer 實例

所有的 ArrayBuffer 物件實例皆繼承自 ArrayBuffer.prototype.

屬性

ArrayBuffer.prototype[Symbol.toStringTag]

The initial value of the Symbol.toStringTag property is the string "ArrayBuffer". This property is used in Object.prototype.toString().

ArrayBuffer.prototype.byteLength

The read-only size, in bytes, of the ArrayBuffer. This is established when the array is constructed and cannot be changed.

方法

ArrayBuffer.prototype.slice()

Returns a new ArrayBuffer whose contents are a copy of this ArrayBuffer's bytes from begin (inclusive) up to end (exclusive). If either begin or end is negative, it refers to an index from the end of the array, as opposed to from the beginning.

範例

In this example, we create a 8-byte buffer with a Int32Array view referring to the buffer:

var buffer = new ArrayBuffer(8);
var view = new Int32Array(buffer);

規範

瀏覽器相容性

相容性備註

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

var dv = ArrayBuffer(10);
// TypeError: calling a builtin ArrayBuffer constructor
// without new is forbidden

var dv = new ArrayBuffer(10);

參見

• TypedArray
• SharedArrayBuffer