对于OOP的一般理解在JavaScript不是阅读Douglas Crockford你不能做的更好:
对于道场的球迷(和一般技术)Neil Roberts有好文章:
平原香草dojo.declare()可能是在围绕主流库中最先进的面向对象的基础。我有偏见,但不要听我的话。这里有一些关于如何使用它的例子。
一个普通的对象:
// Let's define a super simple class (doesn't inherit anything).
dojo.declare("Person", null, {
// Class-level property
answer: 42,
// Class-level object property
name: {first: "Ford", last: "Prefect"},
// The constructor, duh!
constructor: function(age){
this.age = age; // instance-level property
},
// A method
saySomething: function(verb){
console.log("I " + verb + " " +
this.name.first + " " + this.name.last + "!" +
" -- " + this.answer);
},
// Another method
passportControl: function(){
console.log("I am " + this.age);
}
});
使用示例:
// A fan of Ford Perfect
var fan = new Person(18);
fan.saySomething("love"); // I love Ford Perfect! -- 42
fan.passportControl(); // I am 18
单继承很容易:
// Let's create a derived class inheriting Person
dojo.declare("SuperAgent", Person, {
// Redefine class-level property
answer: "shaken, not stirred",
// Redefine class-level object property
name: {first: "James", last: "Bond"},
// The constructor
constructor: function(age, drink){
// We don't need to call the super class because
// it would be done automatically for us passing
// all arguments to it.
// At this point "age" is already assigned.
this.drink = drink; // Instance-level property
},
// Let's redefine the method
saySomething: function(verb){
// Let's call the super class first
this.inherited(arguments);
// Pay attention: no need for extra parameters, or any extra code,
// we don't even name the class we call --- it is all automatic.
// We can call it any time in the body of redefined method
console.log("Yeah, baby!");
},
shoot: function(){ console.log("BAM!!!"); }
});
使用示例:
// Let's create a James Bond-wannabe
var jb007 = new SuperAgent(45, "Martini");
jb007.saySomething("dig"); // I dig James Bond! -- shaken, not stirred
// Yeah, baby!
jb007.passportControl(); // I am 45
jb007.shoot(); // BAM!!!
// Constructors were called in this order: Person, SuperAgent
// saySomething() came from SuperAgent, which called Person
// passportControl() came from Person
// shoot() came from SuperAgent.
混入:
// Let's define one more super simple class
dojo.define("SharpShooter", null, {
// For simplicity no constructor
// One method to clash with SuperAgent
shoot: function(){
console.log("It's jammed! Shoot!");
}
});
基于mixin的
多重继承:
// Multiple inheritance
dojo.declare("FakeAgent", ["SuperAgent", "SharpShooter"], {
// Let's do it with no constructor
// Redefine the method
saySomething: function(verb){
// We don't call super here --- a complete redefinition
console.log("What is " + verb "? I want my " + this.drink + "!");
},
});
使用示例:
// A fake agent coming up
var ap = new FakeAgent(40, "Kool-Aid");
ap.saySomething("hate"); // What is hate? I want my Kool-Aid!
ap.passportControl(); // I am 40
ap.shoot(); // It's jammed! Shoot!
// Constructors were called in this order: Person, SuperAgent
// saySomething() came from FakeAgent
// passportControl() came from Person
// shoot() came from SharpShooter.
正如你所看到的,dojo.declare()
给所有必需品用一个简单的使用API:直接单一继承,基于mixin的多继承,构造函数的自动链接以及无障碍超级方法。
我不知道你能做到这一点,看起来更优雅。感谢您的输入:) +1 – 2008-12-10 14:10:29