async_hooks.createHook(callbacks)

• callbacks <Object> 要注册的钩子回调
  • init <Function> init 回调。
  • before <Function> before 回调。
  • after <Function> after 回调。
  • destroy <Function> destroy 回调。
  • promiseResolve <Function> promiseResolve 回调。
• 返回: <AsyncHook> 用于禁用和启用钩子的实例

为每个异步操作的不同生命周期事件注册要调用的函数。

回调 init()/before()/after()/destroy() 在资源的生命周期内为相应的异步事件调用。

所有回调都是可选的。 比如，如果只需要跟踪资源清理，则只需要传入 destroy 回调。 可以传给 callbacks 的所有函数的细节都在钩子回调章节。

import { createHook } from 'node:async_hooks';

const asyncHook = createHook({
  init(asyncId, type, triggerAsyncId, resource) { },
  destroy(asyncId) { }
});const async_hooks = require('node:async_hooks');

const asyncHook = async_hooks.createHook({
  init(asyncId, type, triggerAsyncId, resource) { },
  destroy(asyncId) { }
});

回调将通过原型链继承：

class MyAsyncCallbacks {
  init(asyncId, type, triggerAsyncId, resource) { }
  destroy(asyncId) {}
}

class MyAddedCallbacks extends MyAsyncCallbacks {
  before(asyncId) { }
  after(asyncId) { }
}

const asyncHook = async_hooks.createHook(new MyAddedCallbacks());

因为 promise 是异步的资源，其生命周期通过异步钩子机制进行跟踪，所以 init()、before()、after() 和 destroy() 回调不能是返回 promise 的异步函数。

• callbacks <Object> The Hook Callbacks to register
  • init <Function> The init callback.
  • before <Function> The before callback.
  • after <Function> The after callback.
  • destroy <Function> The destroy callback.
  • promiseResolve <Function> The promiseResolve callback.
• Returns: <AsyncHook> Instance used for disabling and enabling hooks

Registers functions to be called for different lifetime events of each async operation.

The callbacks init()/before()/after()/destroy() are called for the respective asynchronous event during a resource's lifetime.

All callbacks are optional. For example, if only resource cleanup needs to be tracked, then only the destroy callback needs to be passed. The specifics of all functions that can be passed to callbacks is in the Hook Callbacks section.

import { createHook } from 'node:async_hooks';

const asyncHook = createHook({
  init(asyncId, type, triggerAsyncId, resource) { },
  destroy(asyncId) { }
});const async_hooks = require('node:async_hooks');

const asyncHook = async_hooks.createHook({
  init(asyncId, type, triggerAsyncId, resource) { },
  destroy(asyncId) { }
});

The callbacks will be inherited via the prototype chain:

class MyAsyncCallbacks {
  init(asyncId, type, triggerAsyncId, resource) { }
  destroy(asyncId) {}
}

class MyAddedCallbacks extends MyAsyncCallbacks {
  before(asyncId) { }
  after(asyncId) { }
}

const asyncHook = async_hooks.createHook(new MyAddedCallbacks());

Because promises are asynchronous resources whose lifecycle is tracked via the async hooks mechanism, the init(), before(), after(), and destroy() callbacks must not be async functions that return promises.