*Execution Context *
//📌execution context - a environment , where javascript code is executed and evaluated
//global execution context - by default an execution provided by js ,i.e known as global execution context
//this is the place where the whole code resides.
//eg. consider a example of nesting a loop , then the first loop is global exec context and the rest are
// sub exec context
var a =3;
var b =5;
function sum(a,b)
{
return a+b;
}
var sum1 =sum(5,6);
var sum2=sum(a,b);
console.log(sum1);
console.log(sum2);
*Hoisting *
console.log(a);
greet();
var a =2
function greet()
{
console.log("Hello")
}
Access by Value and Access by reference
// 📌Primitive and Non Primitive data type
//📌 PRIMITIVE DATA TYPE
let a =2.5
console.log(a,typeof(a))
//👉 ans -->2.5 number
let b ="hello"
console.log(b,typeof(b));
//👉ans -->hello string
let c =true
console.log(c,typeof(c));
//👉ans -->true boolean
let d =undefined
console.log(d,typeof(d));
//👉 ans -->undefined undefined
let e =null
console.log(e,typeof(e));
// 👉ans-->null object
//📌Even though null is a primitive data type , it is given object in js (in js - it is treated as missing object)(it is considered as a bug in js till date)
//📌 NON PRIMITIVE DATA TYPE
let firstperson ="hitesh"
let secondperson =firstperson
console.log(firstperson);
console.log(secondperson);
// 👉ans-->
// hitesh
// hitesh
let firstperson1 ="hitesh"
let secondperson1 =firstperson
firstperson1="arshad"
console.log(firstperson1);
console.log(secondperson1);
//👉 ans -->
// arshad
// hitesh
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