Does Var Replace Let

Should I replace var with let ? NO, let is the new block scoping var . … let improves scoping options in JS, not replaces. var is still a useful signal for variables that are used throughout the function.

Should you use VAR or let?

The main difference between the two though is that let deals with block scope whereas var deals with global scope or function scope depending on where it’s declared. As long as your variable isn’t declared within any function, var can be used again anywhere else in your code.

Is VAR faster than let?

In terms of performance comparison, var is faster and let is slower inside the loops while running or executing the code. Re-declaring var declared a variable in the same function or scope gives rise to Syntax Error whereas let declared variable cannot be redeclared.