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The simple difference between var, let and const in Javascript

February 22, 2020

var

A var variable can be re-declared and updated. var is “function scoped”.

The scope of a variable defined with “var” is limited to that “function”. If it is defined outside any function, then the scope of the variable is global.

let

A let variable be be updated but not re-declared. “let” is “block scoped”.

The scope of a variable defined with “let” is limited to the “block” which is defined by curly braces -> {}

const

As per the name suggests, const variables cannot be updated. 

We can not re-assign value to the variable but it CAN be mutated.

Same as "Let", The scope of a variable defined with “let” is limited to the “block” which is defined by curly braces -> {

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