JavaScript/ecommerceWebpage.html at master · vishal-vaish/JavaScript · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>

</body>
</html>
<script>
    const cart=["shoes","pants","kurta"];

    //To place an order

    //1. Create a order
    //2. Proceed to payment
    //3. print order

   // createOrder();
    //because create order is asynchromer, there is possibility that it proceed to payments without creating order
    // so, we use callback function
    function showSummary(){
        console.log("will show summary");
    }

    function createOrder(callback){
        setTimeout(()=>{
            console.log("order created");
            callback();
        },3*1000);
    }

    createOrder(function(){
        proceedToPayment(function(){
           showSummary();
        });
    })

    function proceedToPayment(callback){
        setTimeout(()=>{
        console.log("payment");
        callback();
    },3000);
    }

    //callback Hell or Pyramid of Doom

    //2. Inversion of Control: Does not have sureity that it will work

</script>