Added

one or more of the arrays provided were empty, although the description mentioned that this couldn't happen.

that's not what the description says.

Anyway, the ref solution was incorrect for empty arrays. Corrected.

Tests modified: I parted and lightened them.

Mocha (test framework used for TS and Node 10+) has its own timeout per test case. Looks like this kata has lots of test in one test case and that's making the test framework to timeout before the CW limit.

You can either split the tests into smaller test cases which can also improve feedback. Or you can disable the timeout for the test case by adding this.timeout(0) in it. See Mocha's documentation.

TS translation done by @OpenByte, gone from CW in February. His reference solution passes in less than 5000s as well as some other solutions.
Days ago I was able to see not passed solutions but now I am not able to see and try them. Moreover I had to refresh the page many times before my reply works!

Something could be wrong with the CW environment.

Report a bug? Has something changed? 52 TS solutions have passed.

Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. (/home/codewarrior/ts/test.ts)

Something could be wrong with the CW environment.