WIP: Add type parameter of event subtype for app.message listeners #796

[seratch]

Summary

This pull request shows a possible improvement for #796 use case - better support for message event subtypes in TypeScript. I'm still wondering if there may be a better solution than this one. I would love to get inputs and feedback from anyone who is interested in this topic.

Requirements (place an x in each [ ])

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

[codecov[bot]]

Codecov Report

Merging #871 (3256fee) into main (4365f45) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 3256fee differs from pull request most recent head 0fce896. Consider uploading reports for the commit 0fce896 to get more accurate results

@@           Coverage Diff           @@
##             main     #871   +/-   ##
=======================================
  Coverage   66.08%   66.08%           
=======================================
  Files          13       13           
  Lines        1200     1200           
  Branches      353      353           
=======================================
  Hits          793      793           
  Misses        338      338           
  Partials       69       69           

Impacted Files	Coverage Δ
src/App.ts	82.76% <ø> (ø)

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[seratch]

converted to draft for safety

[seratch]

As we are aiming to release v3.4.0 within a few days and this pull request needs more time, let me move this one to v3.5 milestone.

[seratch]

Let me close this long-lived but incomplete PR. If someone would like to reuse the code changes in the future, go ahead with it! 🚀