您可以在EventEmitter的emit方法上使用`.apply（）`吗？

Question

I'm trying to do...

EventEmitter = require('events').EventEmitter

events = new EventEmitter()

events.emit.apply(null, ['eventname', 'arg1', 'arg2', 'arg3'])

...but it doesn't seem to work or throw an error, any help?

Answer 1

在Apply方法上，您需要通知两个参数：有效范围（该值在方法内部为“ this”）和参数数组。

Answer 2

I think the emit() function of the EventEmitter is expecting this to be an actual EventEmitter object. The following seems to work if you pass in the events object.

events.emit.apply(events, ['eventname', 'arg1', 'arg2', 'arg3'])

Though at this point, might as well just call

emit('eventname', 'arg1', 'arg2', 'arg3')

I am guessing the emit() method is looping over an internal list of registered events to see if there is a matching one. Not sure if this helps, just something I came across today working with events...