events.getEventListeners(emitterOrTarget, eventName)

• emitterOrTarget <EventEmitter> | <EventTarget>
• eventName <string> | <symbol>
• 返回: <Function[]>

返回名为 eventName 的事件的监听器数组的副本。

对于 EventEmitter，这与在触发器上调用 .listeners 的行为完全相同。

对于 EventTarget，这是获取事件目标的事件监听器的唯一方法。 这对于调试和诊断目的很有用。

const { getEventListeners, EventEmitter } = require('events');

{
  const ee = new EventEmitter();
  const listener = () => console.log('Events are fun');
  ee.on('foo', listener);
  getEventListeners(ee, 'foo'); // [listener]
}
{
  const et = new EventTarget();
  const listener = () => console.log('Events are fun');
  et.addEventListener('foo', listener);
  getEventListeners(et, 'foo'); // [listener]
}

• emitterOrTarget <EventEmitter> | <EventTarget>
• eventName <string> | <symbol>
• Returns: <Function[]>

Returns a copy of the array of listeners for the event named eventName.

For EventEmitters this behaves exactly the same as calling .listeners on the emitter.

For EventTargets this is the only way to get the event listeners for the event target. This is useful for debugging and diagnostic purposes.

const { getEventListeners, EventEmitter } = require('events');

{
  const ee = new EventEmitter();
  const listener = () => console.log('Events are fun');
  ee.on('foo', listener);
  getEventListeners(ee, 'foo'); // [listener]
}
{
  const et = new EventTarget();
  const listener = () => console.log('Events are fun');
  et.addEventListener('foo', listener);
  getEventListeners(et, 'foo'); // [listener]
}