Is it bad practice to use the same variable name in multiple for-loops?

Question

I was just linting some JavaScript code using JSHint. In the code I have two for-loops both used like this:

for (var i = 0; i < somevalue; i++) { ... }
         


        

Answer 1

Variables in javascript are function scoped (not block scoped).

When you define var i in a loop, it remains there in loop and also in the function having that loop.

See below,

function myfun() {
    //for-loop 1
    for (var i = 0; ...; i++) { ... }

    // i is already defined, its scope is visible outside of the loop1.
    // so you should do something like this in second loop.

    for (i = 0; ...; j++) { ... }

    // But doing such will be inappropriate, as you will need to remember
    // if `i` has been defined already or not. If not, the `i` would be global variable.
}