How could I express optional tuple element?

[ellemedit]

Following is considered as valid (not thrown):

parse(tuple([string(), optional(string())]), ['test', undefined]);

Following is considered as invalid (thrown):

parse(tuple([string(), optional(string())]), ['test']);

Is this intended behavior? I thought I could skip the rest optional tuple element.

[fabian-hiller]

optional behave this way only for object. A tuple requires a fixed min length. Feel free to create an issue. I will then investigate this case to see if we want to change or improve this behavior. For now, maybe you can use the rest argument as a workaround:

parse(tuple([string()], string()), ['test']);

[ellemedit]

Thank you for suggesting workaround!

I'll discuss with my colleagues and twitters. I'll open an issue if needed.

[ellemedit]

tuple rest parameters considered as a optional parameters?

[fabian-hiller]

Yes. But it allows an infinite amount of it at the end of the tuple. So ['test', 'test', 'test', 'test'] is considered a valid input.