Call (), apply (), bind ()

1. The call () and apply () methods are present in each function object, and in the prototype

2. Grammar is
Function.apply (Thisobj,[a,b,c])

Function.call (THISOBJ,A,B,C)

3. Common Ground

is used to call a method in place of another object, changing the object context of a function to a new object specified by Thisobj

4, different points

Apply () takes two parameters and puts the parameters in the array

Call () accepts multiple parameters, and the argument is a list of strings

5. Example

function Add (A, b) {

return a+b;
}
function Sub (A, b) {
return a-B;
}

var a1 = add.apply (sub,[4,2])

var a2 = sub.apply (add,[4,2])

var a3 = Add.call (sub,4,2)

Console.log (A1,A2,A3)

6. Implementing inheritance

function Animal (name) {
THIS.name = name;
This.showname = function () {
alert (this.name);
}
}

function Cat (name) {
Animal.apply (This,[name]);
}

var cat = new Cat ("cuckoo");
Cat.showname ();

The use of/*call * *
Animal.call (This,name);

Call (), apply (), bind ()