JavaScript apply core complexity as simple

Apply is the default method of the front-end JavaScript method, which is used to replace the This object of the currently executing method, to implement inheritance, or to modify the method to use inside the This object;

This time first said inherit:

For example:

First, declare two methods inside the test method, Add,sub:

function Test () {

This.add=function (A, b) {

return a+b;

}

This.sub=function (A, b) {

return a-B;

}

}

Then, we then define a method Test2:

function Test2 () {

Test.apply (this);

}

Next, we generate the instance T2, in the instantiation process Test2 becomes the T2 constructor function, at this time Test2 method inside the This object refers to T2;

var t2=new test2 ();

So now, we can test T2:

T2.add (2,1);

T2.sub (3,2);

The result is not very magical.

JavaScript apply core complexity as simple