worker.markAsUntransferable(object)

将对象标记为不可传输。 如果 object 出现在 port.postMessage() 调用的传输列表中，则忽略它。

特别是，这对于可以克隆而不是传输的对象，以及被发送方的其他对象使用的对象来说是有意义的。 例如，Node.js 用这个标记了它用于 Buffer 池的 ArrayBuffer。

此操作无法撤消。

const { MessageChannel, markAsUntransferable } = require('node:worker_threads');

const pooledBuffer = new ArrayBuffer(8);
const typedArray1 = new Uint8Array(pooledBuffer);
const typedArray2 = new Float64Array(pooledBuffer);

markAsUntransferable(pooledBuffer);

const { port1 } = new MessageChannel();
port1.postMessage(typedArray1, [ typedArray1.buffer ]);

// 以下行打印 typedArray1 的内容，
// 它仍然拥有它的内存并且已经被克隆，而不是传输。
// 没有 `markAsUntransferable()`，这将打印空的 Uint8Array。
// typedArray2 也完好无损。
console.log(typedArray1);
console.log(typedArray2);

浏览器中没有与此 API 等效的 API。

Mark an object as not transferable. If object occurs in the transfer list of a port.postMessage() call, it is ignored.

In particular, this makes sense for objects that can be cloned, rather than transferred, and which are used by other objects on the sending side. For example, Node.js marks the ArrayBuffers it uses for its Buffer pool with this.

This operation cannot be undone.

const { MessageChannel, markAsUntransferable } = require('node:worker_threads');

const pooledBuffer = new ArrayBuffer(8);
const typedArray1 = new Uint8Array(pooledBuffer);
const typedArray2 = new Float64Array(pooledBuffer);

markAsUntransferable(pooledBuffer);

const { port1 } = new MessageChannel();
port1.postMessage(typedArray1, [ typedArray1.buffer ]);

// The following line prints the contents of typedArray1 -- it still owns
// its memory and has been cloned, not transferred. Without
// `markAsUntransferable()`, this would print an empty Uint8Array.
// typedArray2 is intact as well.
console.log(typedArray1);
console.log(typedArray2);

There is no equivalent to this API in browsers.