假设我有一个名为 Human
的类。
function Human(name, gender, age, personality){
this.name = name;
this.gender = gender;
this.age = age;
this.personality = personality;
}
而且我有一些类的功能,例如greeting
和introduce
。所以我这样创建它们:
Human.prototype.introduce = function() {
var _gender = {"M": "Boy", "F": "Girl"};
switch(this.personality)
{
case "passionate":
alert("Hi, how are you? My name is " + this.name + ". I'm " + this.age + " years old " + _gender[this.gender] + ". ");
break;
case "aggressive":
alert("I'm " + this.name + ". What you want? ");
break;
}
}
Human.prototype.greeting = function() {
alert("Hi!");
}
既然introduce
和greeting
可以归为同一个类别(让我们将其命名为speak
),我怎样才能简单地包装这两个函数与一个对象?我试过这个:
Human.prototype.speak = {};
Human.prototype.speak.greeting = function(){
alert("Hi!");
}
Human.prototype.speak.introduce = function(){
var _gender = {"M": "Boy", "F": "Girl"};
switch(this.personality)
{
case "passionate":
alert("Hi, how are you? My name is " + this.name + ". I'm " + this.age + " years old " + _gender[this.gender] + ". ");
break;
case "aggressive":
alert("I'm " + this.name + ". What you want? ");
break;
}
}
现在的问题是,当一个函数被一个对象包裹时,introduce 函数中的this
不再引用该实例。那么我该如何解决这个问题呢?
我想这样调用这个函数:
var eminem = new Human("Marshall Mathers", "M", 45, "aggressive");
eminem.speak.introduce();
最佳答案
类演讲
让 Speak
成为一个类,因为 OOP 中的变量和功能的逻辑分组是类。
说话
function Speak(human) {
this.human = human
}
Speak.prototype.greeting = function () {
// ...
}
Speak.prototype.introduce = function () {
// ..
}
人类
function Human(name, gender, age, personality, greetWord) {
this.name = name;
this.gender = gender;
this.age = age;
this.personality = personality;
this.speak = new Speak(this)
}
例子
function Human(name, gender, age, personality, greetWord) {
this.name = name;
this.gender = gender;
this.age = age;
this.personality = personality;
this.greetWord = greetWord;
this.speak = new Speak(this)
}
function Speak(human) {
this.human = human
}
Speak.prototype.greeting = function () {
alert(this.human.greetWord + "!");
}
Speak.prototype.introduce = function () {
var _gender = { "M": "Boy", "F": "Girl" };
switch (this.human.personality) {
case "passionate":
alert("Hi, how are you? My name is " + this.human.name + ". I'm " + this.human.age + " years old " + _gender[this.human.gender] + ". ");
break;
case "aggressive":
alert("I'm " + this.human.name + ". What you want? ");
break;
}
}
var peter = new Human('Peter', 'M', 35, 'aggressive', 'Hi')
peter.speak.greeting()
peter.speak.introduce()
解决方案的另一种方法是使用应用。
Apply
The apply() method calls a function with a given this value, and arguments provided as an array (or an array-like object).
代码
var peter = new Human('Peter', 'M', 35, 'aggressive')
console.log(peter.speak.introduce.apply(peter))
例子
function Human(name, gender, age, personality){
this.name = name;
this.gender = gender;
this.age = age;
this.personality = personality;
}
Human.prototype.speak = {};
Human.prototype.speak.greeting = function(){
alert("Hi!");
}
Human.prototype.speak.introduce = function(){
var _gender = {"M": "Boy", "F": "Girl"};
switch(this.personality)
{
case "passionate":
alert("Hi, how are you? My name is " + this.name + ". I'm " + this.age + " years old " + _gender[this.gender] + ". ");
break;
case "aggressive":
alert("I'm " + this.name + ". What you want? ");
break;
}
}
var peter = new Human('Peter', 'M', 35, 'aggressive')
console.log(peter.speak.introduce.apply(peter))
关于javascript - 如何在 javascript 的类中用对象包装函数?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47280342/