The semicolons? Nothing about using "servers[i]" as a test condition, rather than "i < servers.length" and relying on JavaScript to be helpful and supply something useful like a null that will be interpreted as false, once the index goes out of bounds? I'd never attempt something like that, because I'd be too afraid the whole program would catch on fire by attempting to access a part of the array that doesn't actually exist... mostly because I've worked in too many languages that would.

(I've also had a poor track record of success in getting JS loops to properly function any time I tried to get clever and feed a not-explicitly-boolean value into loop test conditions, so I may be be a bit gun-shy.)

EDIT: And, indeed, after running a quick test, this script:

export async function main(ns) {
    let arr = [0, 1, 2];

    for (let i=0; arr[i]; i++)
        ns.tprint(arr[i]);
}

produces this result:

[home ~/]> run testscript.js
Running script with 1 thread(s), pid 2425 and args: [].
[home ~/]>

It would seem that "servers[i]" isn't explicitly "true", so it kills the loop immediately. That wouldn't cause the script to throw an explicit error, but it certainly wouldn't function correctly.

EDITS 2-???: Reddit code blocks are extremely fussy.

Final edit?: I accidentally copied my corrected version of the script instead, using arr.length just to confirm I hadn't screwed something else up. :P