将 AsyncResource 与 EventEmitter 集成

¥Integrating AsyncResource with EventEmitter

由 EventEmitter 触发的事件监听器可能在与调用 eventEmitter.on() 时处于活动状态的执行上下文不同的执行上下文中运行。

¥Event listeners triggered by an EventEmitter may be run in a different execution context than the one that was active when eventEmitter.on() was called.

以下示例显示如何使用 AsyncResource 类将事件监听器与正确的执行上下文正确关联。相同的方法可以应用于 Stream 或类似的事件驱动类。

¥The following example shows how to use the AsyncResource class to properly associate an event listener with the correct execution context. The same approach can be applied to a Stream or a similar event-driven class.

import { createServer } from 'node:http';
import { AsyncResource, executionAsyncId } from 'node:async_hooks';

const server = createServer((req, res) => {
  req.on('close', AsyncResource.bind(() => {
    // Execution context is bound to the current outer scope.
  }));
  req.on('close', () => {
    // Execution context is bound to the scope that caused 'close' to emit.
  });
  res.end();
}).listen(3000);const { createServer } = require('node:http');
const { AsyncResource, executionAsyncId } = require('node:async_hooks');

const server = createServer((req, res) => {
  req.on('close', AsyncResource.bind(() => {
    // Execution context is bound to the current outer scope.
  }));
  req.on('close', () => {
    // Execution context is bound to the scope that caused 'close' to emit.
  });
  res.end();
}).listen(3000);拷贝