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

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<!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>
    function x(){
        var a=7;
        function y(){
            //1. It will check the local memory
            //2. Lexical Parent
            //3. Parent Lexical Scope+ Local Memory
            console.log(a);
        }
        return y;
    }
    var z=x();
    console.log("z is:",z);
    //type of z--> function
    //z();

    //function bundled along with it's lexical scope is closure

    //when y is returned, not only the function is returned but the entire closue(function+ lexical scope)

    function z(){
        var b=900;
        function x(){
            var a=7;
            function y(){
                console.log(a,b);
            }
            y();
        }
        x();
    }
    z();

    //A closure is a function that has access to its outer function scope even after the function is returned

</script>