Somebody submitted that code when the tests were too weak to catch such wrong solutions.

There should be fixed tests with all letters in range "a" - "m", and all letters in range "n" - "z".

This is the code that I copied from the first answer that appears for Javascript tho. Yet it still fails even tho apparently it was correct when someone else did it. Is there a possible reason why that you could tell me?

Edit for context: the code in the above comment is the top answer for JS. Yet when i press attempt, it returns 196 correct answers and 5 errors.

Your "definitely correct" code fails for the simplest inputs, e.g. printerError("a"). Not an issue.

I get the same error and have no clue whats going on

it converts operand to number

okay but why does everyone put a + at the front? what does the + do that makes it necessary for this code?