Convert to Typescript w/ ESLint

[avatarneil]

Is your feature request related to a problem? Please describe.
As a new developer to the project, a combination of Typescript & ESLint would be helpful when validating possible side-effects of changes.

Describe the solution you'd like
Migrate project to Typescript with ESLint.

Describe alternatives you've considered
cries in vanilla js

[kelvinfan001]

I have limited knowledge in this area, but I've heard good things about Typescript, so definitely open to this conversion!

[avatarneil]

I have a bit of a love-hate relationship with Typescript, but it's definitely nicer than vanilla JS IMO. We can start out making the compiler rules really permissive (allow implicit any types, no strict-null checking, etc) and then migrate over time to stricter rules. There is a reasonably large project I work on which we migrated from JS -> TS about a year and a half ago, and given how large that project is relative to this one, I have high confidence the migration wouldn't be too bad!

[avatarneil]

Gonna spike a PR adding eslint/prettier project-wide with a config I like, so you can see how it looks! It's already pointing out some tiny bugs :)

[kelvinfan001]

Sounds good! Hopefully it'll help force us to clean up the project while we're at it.

It's already pointing out some tiny bugs :)

I'm fairly confident larger ones will be emerging soon.