Breaking News: Grepper is joining You.com. Read the official announcement!

var vs let vs const

Add Answer

GitPaulo answered on August 17, 2020 Popularity 10/10 Helpfulness 6/10

answer var vs let vs const

related let vs const

related diff between let var const

related difference between var, let, const

var vs let vs const

Comment

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.

Popularity 10/10 Helpfulness 6/10 Language whatever

Source: Grepper

Tags: let var whatever

Link to this answer
Share Copy Link

Contributed on May 11 2021

GitPaulo

0 Answers Avg Quality 2/10

Closely Related Answers

let vs const

Comment

`const` is a signal that the identifier won't be reassigned.

`let` is a signal that the variable may be reassigned, such as a counter in a
loop, or a value swap in an algorithm.

It also signals that the variable will be used only in the block it's defined
in, which is not always the entire containing function.

Popularity 10/10 Helpfulness 4/10 Language whatever

Source: Grepper

Tags: let

Link to this answer
Share Copy Link

Contributed on Aug 17 2020

Fylls

0 Answers Avg Quality 2/10

diff between let var const

Comment

Difference between let var const
	
	Var, Let, Const keywords introduced in ES6 (2015).
	1] Var:
		Var can reassign value
		Var can have global or local scope
	2] Let:
		Let can not be redeclared.
		Let have block scope.
		Let can reassign value
	3] Const:
		Const cannot be Redeclared.
		Const cannot be Reassigned.
		Const have Block Scope.

Popularity 10/10 Helpfulness 3/10 Language javascript

Source: Grepper

Tags: between

Link to this answer
Share Copy Link

Contributed on Mar 31 2023

@CodeGrepperManu

0 Answers Avg Quality 2/10

difference between var, let, const

Comment

// 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 
}

Popularity 10/10 Helpfulness 2/10 Language javascript

Source: raw.githubusercontent.com

Tags: between

Link to this answer
Share Copy Link

Contributed on Sep 13 2021

Md. Asif Iqbal

0 Answers Avg Quality 2/10

var vs let vs const

Contents

More Related Answers

var vs let vs const

Closely Related Answers

let vs const

diff between let var const

difference between var, let, const

Grepper

Documentation

Social

Legal

Contact

Oops, You will need to install Grepper and log-in to perform this action.