Let in Javascript
JavaScript let
keyword is used to declare block-scoped variables.
It was introduced in ECMAScript 6 as an alternative to var
, which declares variables in the global or function scope.
The key difference is that let
variables are block-scoped, while var
variables are function or global scoped.
Declaring a variable with let
let x = 42;
This code declares a block-scoped variable x
and initializes it with the value 42
. x
can only be accessed within the block it's declared in.
Example
let x = 42;
console.log(x); // 42
Here:
- We declared a variable
x
usinglet
and initialized it with the value42
. - We logged the value of
x
to the console.
Importantance of Let
Here are some important points about the let keyword in JavaScript:
let
are block-scoped.let
must be declared before use.let
cannot be redeclared.let
cannot be hoisted.