call js

1function Product(name, price) {
2  this.name = name;
3  this.price = price;
4
5  if (price < 0)
6    throw RangeError('Cannot create product "' + name + '" with a negative price');
7  return this;
8}
9
10function Food(name, price) {
11  Product.call(this, name, price);
12  this.category = 'food';
13}
14Food.prototype = new Product();
15
16function Toy(name, price) {
17  Product.call(this, name, price);
18  this.category = 'toy';
19}
20Toy.prototype = new Product();
21
22var cheese = new Food('feta', 5);
23var fun = new Toy('robot', 40);

1// let us see what exactly CALL, BIND method in JS
2
3/* NOTE : (CALL , APPLY executes immediately) and
4(BOUND - it returns bounded function that execute later)
5
6NOTE : call will take its additinal arguments just like that 
7	   eg : XYZ.call(this , a , b , c);
8       
9NOTE : apply will take its additinal arguments as an ARRAY
10       eg : XYZ.apply(this , [a , b , c])
11
12NOTE : All of them are for borrowing values(property and methods)
13	   from another function
14*/
15
16/*CALL method  {let's say we have constructor func}, we need all these
17properties and methods in another function, in that way CALL is 
18highly useful */
19function Person(name,place){
20    this.name = name;
21    this.place = place;
22    this.greet = function(){
23        return (`HEllo I am ${this.name} comes from ${this.place}`);
24    }
25};
26
27//I need above func prop,methods in below, let's see how to get
28function Teacher(name,place,sub){
29	this.sub = sub;
30 //since i get name,place from Person function I no need to mention here
31    Person.call(this , name , place); 
32  	this.greeting = function(){
33		return(`I am ${name}, from ${place} and I teach ${this.sub}`);
34	}
35 /* also here, we don't need to mention (this.name / this.place) because,
36   we call them here and (this) referes to current Teacher context. try 
37   inheriting below and check in console.
38 */
39}
40
41var Te1 = new Teacher("Ranjan" , "Salem" , "JavaScript");
42    Te1 // all prop and methods
43    Te1.name // Ranjan
44	Te1.place //Salem
45	Te1.greeting() // I am Ranjan, from Salem and I teach JavaScript
46
47
48
49
50// for BIND
51function Student(name,place,like){
52	this.like = like;
53 //since i get name,place from Person function I no need to mention here
54    Person.apply(this , [name , place]); 
55  	this.about_me = function(){
56		return(`My name is  ${name}, I come from ${place} and I
57                like to play${this.like}`);
58	}
59}
60  
61var Pe1 = new Student("Max" , "Mettur" , "Cricket");
62    Pe1 // all prop and methods
63    Pe1.name // Max
64  	Pe1.place // Metttur
65    Pe1.about_me() // My name is Max, I come from Mettur and I like to play cricket