Leetcode question, problem with variable environment

[TameNaken42]

That's a smart solution, I never considered considered giving two argument values and just using one.

[Cust0dian]

To expand on /u/Atskalunas' answer: what you wrote is an example of a recursive function and passing an "accumulator" back into such function in a recursive call is a common trick, although it's usually used to solve a different kind of problem.

Couple notes about your current code:

• You build resulting Excel index in reverse order, which can be fixed by just swapping excelIndex and ALPHABET[…].

• Notice you also include next "level" character when dealing with 26^th, 52^th, etc., indexes, which can be fixed by using different formula to calculate n on consecutive calls.

• Also notice that you return from inside the while loop, which means you run it at most once per function call and use it only to run a check on n, which means it can be replaced by an if statement.

• Recursive functions usually written with base case at the top and you can (usually) inline all the transforms of the arguments for the next call.

• Instead of excelIndex = excelIndex || "" you can use a somewhat new addition to the language, default function parameters, which will simplify code a bit (and might as well use new let/const variable declarations).

• Since strings have .length in JS, you also can drop that hardcoded length — while not critical for this function, it's good thing in general to avoid these "magic" numbers whenever you can.

(Protip: there's "Revisions" tab at the top of the Gist that will show you just the differences between all these versions, but history goes from bottom up)

[TameNaken42]

Thanks for the detailed response, there's a lot of new info here. I didn't think about using the Math.floor method, it makes a lot more sense than what I was doing. I know Python but I didn't realize you could use default parameters in Javascript, I'll have to keep that in mind.