ArrayBuffer.prototype.transferToFixedLength()

¥Syntax

transferToFixedLength()
transferToFixedLength(newByteLength)

¥Parameters

newByteLength

新款 ArrayBuffer 的 byteLength。默认为该 ArrayBuffer 的 byteLength。

• 如果 newByteLength 小于这个 ArrayBuffer 的 byteLength，则 "overflowing" 字节被丢弃。
• 如果 newByteLength 大于该 ArrayBuffer 的 byteLength，则多余的字节用零填充。

¥Return value

一个新的 ArrayBuffer 对象。其内容被初始化为该 ArrayBuffer 的内容，并且额外的字节（如果有）用零填充。新的 ArrayBuffer 始终不可调整大小。原来的 ArrayBuffer 已分离。

¥A new ArrayBuffer object. Its contents are initialized to the contents of this ArrayBuffer, and extra bytes, if any, are filled with zeros. The new ArrayBuffer is always non-resizable. The original ArrayBuffer is detached.

¥Exceptions

TypeError

如果此 ArrayBuffer 已分离，则抛出此异常。

¥Description

与 transfer() 不同，transferToFixedLength() 始终创建不可调整大小的 ArrayBuffer。这意味着 newByteLength 可以大于 maxByteLength，即使 ArrayBuffer 的大小是可调整的。请参阅 传输 ArrayBuffer 了解更多信息。

¥Unlike transfer(), transferToFixedLength() always creates a non-resizable ArrayBuffer. This means newByteLength can be larger than the maxByteLength, even if this ArrayBuffer is resizable. See transferring ArrayBuffers for more information.

¥Examples

¥Transferring a resizable ArrayBuffer to fixed-length

const buffer = new ArrayBuffer(8, { maxByteLength: 16 });
const view = new Uint8Array(buffer);
view[1] = 2;
view[7] = 4;

const buffer2 = buffer.transferToFixedLength();
console.log(buffer2.byteLength); // 8
console.log(buffer2.resizable); // false
const view2 = new Uint8Array(buffer2);
console.log(view2[1]); // 2
console.log(view2[7]); // 4

使用 transferToFixedLength，newByteLength 可以比原来的 ArrayBuffer 的 maxByteLength 大。

¥Using transferToFixedLength, newByteLength can be larger than the maxByteLength of the original ArrayBuffer.

const buffer = new ArrayBuffer(8, { maxByteLength: 16 });
const view = new Uint8Array(buffer);
view[1] = 2;
view[7] = 4;

const buffer2 = buffer.transferToFixedLength(20);
console.log(buffer2.byteLength); // 20
console.log(buffer2.resizable); // false
const view2 = new Uint8Array(buffer2);
console.log(view2[1]); // 2
console.log(view2[7]); // 4

¥See also

• core-js 中 ArrayBuffer.prototype.transferToFixedLength() 的 Polyfill
• ArrayBuffer
• ArrayBuffer.prototype.detached
• ArrayBuffer.prototype.transfer()