我有以下代码定义了一个Car
。每个Car
都有颜色,以及一个setColor(color)
函数。我想添加监听器函数,每当调用setColor(color)
时就会调用它们,并且我希望能够随时附加这些监听器函数。这种方法合适吗?是否有更简洁的方法?
function Car() {
this._color = 'red';
this._callbacks = {};
this.setColor = function(color) {
this._color = color;
console.log(">>> set car color to " + color);
if (this._callbacks['setColor']) {
this._callbacks['setColor']();
}
};
this.addListener = function(functionName, handler) {
if (this._callbacks[functionName]) {
var oldCallback = this._callbacks[functionName];
this._callbacks[functionName] = function() {
oldCallback();
handler();
}
} else {
this._callbacks[functionName] = function() {
handler();
}
}
};
}
var car = new Car();
car.setColor('blue');
car.addListener('setColor', function() { console.log("This is listener # 1"); });
car.setColor('green');
car.addListener('setColor', function() { console.log("This is listener # 2"); });
car.setColor('orange');
输出:
>>> setColor to blue
>>> setColor to green
This is listener # 1
>>> setColor to orange
This is listener # 1
This is listener # 2
color
和callbacks
的半私有性,并将回调函数放在一个数组中而不是闭包中。 - Andrew