Croner returns different values in case of trailing whitespace

[haggholm]

Describe the bug

If a cron expression has trailing whitespace, Croner appears to ‘hallucinate’ an extra (empty?) field. At a first guess I'd suggest that maybe it chooses mode depending on the number of results from something like string.split().

To Reproduce

require("croner")("0 0 12 9 *").nextRuns(3);

→

[
  2024-09-12T07:01:00.000Z,
  2025-09-12T07:01:00.000Z,
  2026-09-12T07:01:00.000Z
]

But

require("croner")("0 0 12 9 * ").nextRuns(3);

→

[
  2023-11-09T20:00:00.000Z,
  2023-12-09T20:00:00.000Z,
  2024-01-09T20:00:00.000Z
]

Expected behavior
A clear and concise description of what you expected to happen.

I'd expect it to either trim the input expression and ignore extraneous whitespace, or failing that, throw an error. It's very surprising to get different results based on a trailing space.

System:

• OS: Linux
• Runtime: Node.js 16
• Croner version: 7.0.0

Additional context
Add any other context about the problem here.

[Hexagon]

@haggholm Issue confirmed 👍

When using a trailing space together with a five part pattern, it's treated as a six part pattern with an empty instruction for weekdays - which interestingly enough is accepted and treated as a wildcard. I will figure out a good solution to this, along with some additional tests.

[Hexagon]

This issue is resolved in croner@dev or [email protected] by throwing on empty parts (which in this case is caused by a trailing space).