var vs let vs const example
Example 1: var vs let vs const
var:
- hoisted (always declared at top of scope, global if none)
- function scope
let:
- block scope
- not redeclarable
const:
- block scope
- not reassignable
- not redeclarable
Note: Although it may seem like these hold only semantic meaning, using the
appropriate keywords helps the JS engines' compiler to decide on what to optimize.
Example 2: difference between var let and const in javascript with example
var a;
a=10;
let a;
a=10;
let a =20;
if(true){
let b =30;
}
console.log(b);
const
const a;
const a =20;
if(true){
const b =30;
}
console.log(b);
console.log(a);