Created
October 17, 2018 06:33
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仿Vue的EventEmitter实现
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var EventEmiter = function (){ | |
this._events = {}; | |
}; | |
EventEmiter.prototype.on = function (event, cb){ | |
if (Array.isArray(event)){ | |
for (let i = 0, l = event.length; i < l; i++){ | |
this.on(event[i], cb); | |
} | |
} else { | |
(this._events[event] || (this._events[event] = [])).push(cb); | |
} | |
return this; | |
}; | |
EventEmiter.prototype.once = function (event, cb){ | |
function on () { | |
this.off(event, cb); | |
cb.apply(this, arguments); | |
} | |
on.fn = cb; | |
this.on(event, on); | |
return this; | |
}; | |
EventEmiter.prototype.off = function (event, cb){ | |
if (!arguments.length){ | |
this._events = Object.create(null); | |
return this; | |
} | |
if (Array.isArray(event)){ | |
for (let i = 0, l = event.length; i < l; i++){ | |
this.off(event[i],cb); | |
} | |
return this; | |
} | |
if (!cb){ | |
this._events[event] = null; | |
return this; | |
} | |
if (cb){ | |
let cbs = this._events[event]; | |
let i = cbs.length; | |
while(i--){ | |
if (cb === cbs[i] || cb === cbs[i].fn){ | |
cbs.splice(i, 1); | |
break; | |
} | |
} | |
return this; | |
} | |
}; | |
EventEmiter.prototype.emit = function (event){ | |
let cbs = this._events[event]; | |
let args = Array.prototype.slice.call(arguments, 1); | |
if (cbs){ | |
for (let i = 0, l = cbs.length; i < l; i++){ | |
cbs[i].apply(this,args); | |
} | |
} | |
}; |
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