javascript call 28 29 26 apply 28 29 vs bind 28 29 3f

1Differentce between .bind() , .call() and .apply()
2
3.bind(someobj) -> does not invoke the function, it just allows you to 
4bind whatever object you want, you have to call the function yourself.
5
6.call(someobj) and .apply(someobj)-> both invoke the function 
7immediately,and modify the context. 
8The only difference is how you pass your
9own arguments. See below
10
11.call(someobj, param1, param2)
12.apply(someobj, [param1, param2]) //uses array to pass the args
13
14
15

1Apply vs. Call vs. Bind Examples
2
3Call
4
5var person1 = {firstName: 'Jon', lastName: 'Kuperman'};
6var person2 = {firstName: 'Kelly', lastName: 'King'};
7
8function say(greeting) {
9    console.log(greeting + ' ' + this.firstName + ' ' + this.lastName);
10}
11
12say.call(person1, 'Hello'); // Hello Jon Kuperman
13say.call(person2, 'Hello'); // Hello Kelly King
14
15Apply
16
17var person1 = {firstName: 'Jon', lastName: 'Kuperman'};
18var person2 = {firstName: 'Kelly', lastName: 'King'};
19
20function say(greeting) {
21    console.log(greeting + ' ' + this.firstName + ' ' + this.lastName);
22}
23
24say.apply(person1, ['Hello']); // Hello Jon Kuperman
25say.apply(person2, ['Hello']); // Hello Kelly King
26
27Bind
28
29var person1 = {firstName: 'Jon', lastName: 'Kuperman'};
30var person2 = {firstName: 'Kelly', lastName: 'King'};
31
32function say() {
33    console.log('Hello ' + this.firstName + ' ' + this.lastName);
34}
35
36var sayHelloJon = say.bind(person1);
37var sayHelloKelly = say.bind(person2);
38
39sayHelloJon(); // Hello Jon Kuperman
40sayHelloKelly(); // Hello Kelly King