difference in var let and const
var:
* hoisted(global scope)
* function scope
let:
* block scope
* reassignable
* not redeclarable
const:
* block scope
* not reassignable
* not redeclarabledifference in var let and const
var:
* hoisted(global scope)
* function scope
let:
* block scope
* reassignable
* not redeclarable
const:
* block scope
* not reassignable
* not redeclarabledifference between var, let, const
// var is a function scope ***
if(true){
var varVariable = 'This is var';
var varVariable = 'This is var again';
}
console.log(varVariable); // This is var again
// let is a block scope ***
if(true){
let letVariable = 'This is let';
let letVariable = 'This is let again';
// let variable can't re-define but we can re-assign value
console.log(letVariable); // let letVariable = 'This is let again';^SyntaxError: Identifier 'letVariable' has already been declared
}
console.log(letVariable); //ReferenceError: letVariable is not defined
// const variable can't re-define and re-assign value
// const is a block scope ***
if(true){
const constVarible = {
name: 'JavaScript',
age: '25 years',
};
constVarible.name = 'JS';
console.log(constVarible) // {name: 'JS',age: '25 years'} <= we can update const variable declared object
}Copyright © 2021 Codeinu
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