Day39Shallowanddeepcopy.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Day 39</title>
</head>
<body>
    <script>
        //shallow copy
        let shal1={
            can1:'dhoni',
            can2:'raina'
        }
        
        let shal2=shal1; //copying objects ----shallowcopy in other words
        shal2.can2='Ashwin';// changing element in copied object
        console.log(shal1); //{can1:'dhoni',can2:'Ashwin'}

        let shal3={...shal1}; // copying objects using spread operator--- i will create new ref in heap
        shal3.can1='Dada';// only change the shal3
        console.log(shal1);// No change in orginial object--- {can1:'dhoni',can2:'Ashwin'}

        // deep copy

        let deepco1={
            firstname:'ponmani',
            lastname:'venkatesan',
            address:{
                District:'Vellore',
                state:'tamilnadu',
                country:'india'
            }
        }

        let deepco2={...deepco1};// still; it copies only firstlevel without ref , not nested one
        deepco2.address.District='chennai';
        console.log(deepco2.address.District);//chennai
        console.log(deepco1.address.District);// here too chennai

        let deepco3=JSON.parse(JSON.stringify(deepco1));
         deepco3.address.District='bangalore';
         console.log(deepco1.address.District);// chennai -- not changed because we copied deeply all the nested objs
         
    </script>
</body>
</html>