.lengthOf should work for sets and maps

[rijnhard]

sets and maps use a different property .size for their length but in the context of chai it should work the same way.

expect(new Set([1])).to.have.lengthOf(1);
// currently UncaughtException AssertionError: expected {} to have property 'length'

[rijnhard]

workaround is:

expect(new Set([1])).to.have.property('size', 1);

[lucasfcosta]

I think this is a very valid suggestion.

If other maintainers agree, I'd love to get this into our codebase.

Btw, this is very similar to #1096.

[meeber]

Agreed. May also be worth adding .size as an alias to .lengthOf.

[keithamus]

PRs welcome for this! Let me know if anyone planning to make a PR would like some assistance

[asbish]

@keithamus I would like to do it by this weekend. Fine with you?

[keithamus]

@asbish that would be more than fine. That would be wonderful!

[keithamus]

@asbish I have assigned this to myself, and removed the pull-request-wanted label - this is so that you have time to make this PR without any one thinking it is free to work on. However, there is no pressure! If you decide you dont or cant work on it any more please let me know 😄

[asbish]

@keithamus Thank you for your kinds words! :)

[keithamus]

hey @rijnhard thanks for this issue!

We're adding this in chai 5, we've added this to our Roadmap https://github.com/chaijs/chai/projects/2! We'll be releasing chai 5 soon, but for now I'll close this issue because it is tracked on our roadmap.