One of the implementation of JavaScript class inheritance

One of the implementation of JavaScript class inheritance

Many JavaScript class inheritance methods have emerged in various blog forums on the Internet. I have browsed some of them, either without comments or without running effects, so I wrote a concise and easy-to-understand version, the accompanying test code is at the bottom.

I accidentally deleted this article, so I made it up again and added an example.

(Function (){

Function. prototype. extend = function (baseClass ){

// This is a function object.
Var oldPrototype = this. prototype, newPrototype = {}, _ super = new baseClass ();

// Inherits all properties and methods.
For (var name in _ super ){
NewPrototype [name] = _ super [name];
}

For (var name in oldPrototype ){
// Only override properties in this new Class.
If (oldPrototype. hasOwnProperty (name )){
// Only function need _ super.
If (typeof oldPrototype [name] = "function" & typeof _ super [name] = "function "){
NewPrototype [name] = (function (name, fn ){
Return function (){
Var tmp = this. _ super;

// Set super method
This. _ super = _ super [name];

Var ret = fn. apply (this, arguments );

This. _ super = tmp;

Return ret;
};
}) (Name, oldPrototype [name]);
}
}
}

This. prototype = newPrototype;

Return this;
};
})();

Var A = function (){
This. hello = function (){
Console. log ("hello, I'm ");
}
};

Var B = function (){};

B. prototype = {
Hello: function (){
This. _ super ();

Console. log ("hello, I'm B ");
}
};

B. extend ();

Var C = function (){};

C. prototype = {
Hello: function (){
This. _ super ();

Console. log ("hello, I'm C ");
}
};

C. extend (B );

Var B = new B ();
Var c = new C ();

// B. hello ();
C. hello ();