emitter.emit(eventName[, ...args])

• eventName <string> | <symbol>

• ...args <any>

• 返回:<boolean>

  \Returns: <boolean>

按注册顺序同步地调用为名为 eventName 的事件注册的每个监听器,并将提供的参数传给每个监听器。

\Synchronously calls each of the listeners registered for the event named eventName, in the order they were registered, passing the supplied arguments to each.

如果事件有监听器,则返回 true,否则返回 false。

\Returns true if the event had listeners, false otherwise.

import { EventEmitter } from 'node:events';
const myEmitter = new EventEmitter();
// First listener
myEmitter.on('event', function firstListener() {
 console.log('Helloooo! first listener');
});
// Second listener
myEmitter.on('event', function secondListener(arg1, arg2) {
 console.log(`event with parameters ${arg1}, ${arg2} in second listener`);
});
// Third listener
myEmitter.on('event', function thirdListener(...args) {
 const parameters = args.join(', ');
 console.log(`event with parameters ${parameters} in third listener`);
});
console.log(myEmitter.listeners('event'));
myEmitter.emit('event', 1, 2, 3, 4, 5);
// Prints:
// [
// [Function: firstListener],
// [Function: secondListener],
// [Function: thirdListener]
// ]
// Helloooo! first listener
// event with parameters 1, 2 in second listener
// event with parameters 1, 2, 3, 4, 5 in third listenerconst EventEmitter = require('node:events');
const myEmitter = new EventEmitter();
// First listener
myEmitter.on('event', function firstListener() {
 console.log('Helloooo! first listener');
});
// Second listener
myEmitter.on('event', function secondListener(arg1, arg2) {
 console.log(`event with parameters ${arg1}, ${arg2} in second listener`);
});
// Third listener
myEmitter.on('event', function thirdListener(...args) {
 const parameters = args.join(', ');
 console.log(`event with parameters ${parameters} in third listener`);
});
console.log(myEmitter.listeners('event'));
myEmitter.emit('event', 1, 2, 3, 4, 5);
// Prints:
// [
// [Function: firstListener],
// [Function: secondListener],
// [Function: thirdListener]
// ]
// Helloooo! first listener
// event with parameters 1, 2 in second listener
// event with parameters 1, 2, 3, 4, 5 in third listener拷贝