The let keyword in JavaScript is used to declare variables that are limited in scope to the block, statement, or expression in which they are used. This is in contrast to the var keyword, which defines a variable globally or locally to an entire function regardless of block scope.
Introduced in ECMAScript 6 (ES6) in 2015, let addresses some of the common pitfalls that developers encountered with var. One of the key differences between let and var is that let allows for block-level scoping. This means that a variable declared with let inside a block {...} is not accessible outside of that block, which can help prevent variables from being accessed or modified when they shouldn't be[1][3][4][5][6][7][8][9][10][11].
Another important aspect of let is that it does not permit redeclaration within the same scope. If you declare a variable with let within a block, you cannot declare another variable with the same name within that block. However, you can declare the same variable name in different blocks[1][3][4][5][6][7][8][9][10][11].
Variables declared with let are also subject to the Temporal Dead Zone (TDZ), which means they cannot be accessed until after they have been declared and initialized. Attempting to access a let variable before its declaration will result in a ReferenceError. This is different from var-declared variables, which are hoisted to the top of their enclosing scope and can be accessed befor...
