Difference between var, let, and const in JS

Question

Accepted Answer

var, let, and const are used to declare variables in JavaScript with different scoping and mutability.

var has function scope and can be redeclared and reassigned
let has block scope and can be reassigned but not redeclared
const has block scope and cannot be reassigned or redeclared

Accepted Answer

1.var: The var keyword was traditionally used to declare variables in JavaScript before the introduction of let and const. Variables declared with var have a function scope or global scope, meaning they are accessible anywhere within the function or in the global scope

let: The let keyword was introduced in ES6 (ECMAScript 2015) and allows block-scoping. Variables declared with let have a block scope, meaning they are only accessible within the block in which they were declared.
const: The const keyword is also introduced in ES6 and allows block-scoping. Variables declared with const are also block-scoped and cannot be reassigned, meaning their value cannot be changed once it has been set

Difference between var, let, and const in JS

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