Allow command handlers to match regexes

[itowlson]

Summary

The App#command method currently only subscribes to a specific slash command identified by exact name. In a few cases it is useful to have more flexibility - for example, a gateway that transforms commands into messages for another system might need to be agnostic about which specific commands the user wants to use it with. This PR adds a RegExp option to the App#command signature, which enables this and related behaviours.

Fixes #841.

Notes to reviewers

• I was not sure how the tests fitted together. I would welcome feedback or guidance on what I've done.
• There is an issue of what happens if the user supplies multiple overlapping regexes, e.g. app.command(/h*/) and app.command(/he*/). I followed the behaviour of shortcut here, where if it runs the listener for all matching regexes. This may be surprising/unwelcome but it is at least consistent. I documented the shortcut behaviour as part of this; but it may be that you prefer to leave this undefined or say it's unsupported so people don't take a dependency on the current behaviour. Note this is distinct from Issue 281 message array support #761 where the regexes could be passed in an array in a single message call (and therefore were looped over within a single piece of middleware). Again I'd welcome feedback or guidance on this!

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #846 (9b17e71) into main (0e469c9) will increase coverage by 0.08%.
The diff coverage is 100.00%.

❗ Current head 9b17e71 differs from pull request most recent head 385cc5f. Consider uploading reports for the commit 385cc5f to get more accurate results

@@            Coverage Diff             @@
##             main     #846      +/-   ##
==========================================
+ Coverage   65.89%   65.98%   +0.08%     
==========================================
  Files          13       13              
  Lines        1173     1176       +3     
  Branches      343      344       +1     
==========================================
+ Hits          773      776       +3     
  Misses        334      334              
  Partials       66       66              

Impacted Files	Coverage Δ
src/App.ts	83.63% <ø> (ø)
src/middleware/builtin.ts	84.09% <100.00%> (+0.36%)	⬆️

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[seratch]

@itowlson You're so quick! Thanks a lot for taking the time to make this pull request 🙇

I was not sure how the tests fitted together. I would welcome feedback or guidance on what I've done.

The added tests cover all the possible patterns. Perfect 👍

I followed the behaviour of shortcut here, where if it runs the listener for all matching regexes. This may be surprising/unwelcome but it is at least consistent.

This is intended behavior in Bolt for JS. Thanks for clarifying this.

I documented the shortcut behaviour as part of this; but it may be that you prefer to leave this undefined or say it's unsupported so people don't take a dependency on the current behaviour. Note this is distinct from #761 where the regexes could be passed in an array in a single message call (and therefore were looped over within a single piece of middleware). Again I'd welcome feedback or guidance on this!

The changes look good to me. In the future, we may want to improve the duplication but we can do it separately.

If you don't mind, could you send another pull request for the document changes? Merging document changes updates the live website immediately. We would like to merge the document updates right after releasing a new version including your change. Once you move the doc changes to another PR, we will merge the code changes!

[seratch]

Once this pull request does not include the document changes, we can merge this PR 👍

[itowlson]

Sorry about that @seratch, I noticed some remarks about documentation in the contributor's guide but I overlooked them when it came to doing the PR. I'll back those out and create a new one for them.

[itowlson]

Docs backed out and moved to #847.

[seratch]

@itowlson Thanks again for your prompt work 👍 I'm sure this is great and already ready for merge but, just in case, I will wait for other maintainers for one business day before merging it.

[mwbrooks]

Fantastic work @itowlson! 🎉 Thanks a lot for contribution!