因爲「macek」(順便感謝)的回答這不是一個正確的答案,但是一個「解決方法」,這對我很有好處。也許別人也幫助了。
var events = require('events');
var myString = function(val){
this.myVal = val;
this.change = function(newVal)
{
if(newVal !== this.myVal){
this.myVal = newVal;
this.emit('changed');
}
}
this.val = function(){
return this.myVal;
}
};
myString.prototype.__proto__ = events.EventEmitter.prototype;
var doSomething = function(){
console.log('string changed');
};
var somestring = new myString('');
console.log(somestring.val()); // output ''
somestring.on('changed',doSomething);
somestring.change('new'); //output doSomething() -> 'string changed'
console.log(somestring.val()); //output 'new'