Use TypeScript to 'compile' our JS snippets

[samtstern]

Right now it's easy to write snippets in this repo which won't actually work, which somewhat defeats the point.

We can use TypeScript to get much better checking on our JS snippets because many of our deps (like firebase-admin) ship with types.

This helped me find a bunch of useful errors in the auth module, although I am stuck on a few.

Valid remaining errors (our stuff is actually broken):

manage_users.js(46,14): error TS2551: Property 'getUsers' does not exist on type 'Auth'. Did you mean 'getUser'?
manage_users.js(132,14): error TS2551: Property 'deleteUsers' does not exist on type 'Auth'. Did you mean 'deleteUser'?

Invalid remaining errors (I need help with these):

custom_claims.js(31,39): error TS2339: Property 'admin' does not exist on type 'Object'.
custom_claims.js(55,27): error TS2339: Property 'admin' does not exist on type 'Object'.
get_service_account_tokens.js(20,32): error TS2732: Cannot find module 'path/to/serviceAccountKey.json'. Consider using '--resolveJsonModule' to import module with '.json' extension

[samtstern]

@abeisgoat @jhuleatt @jamesdaniels would love to know your thoughts on this method.

[jhuleatt]

One way to resolve TS errors is to annotate types with comments in the JS files. Might help with the Property 'admin' does not exist on type 'Object' warnings

[samtstern]

@jhuleatt you're OOO get outta here! But thank you.

[samtstern]

This now fails for the right reasons: auth contains snippets for an unreleased SDK (bulk user fetch/delete)

[jhuleatt]

Was this switched from customClaims.admin to customClaims['admin'] here and below to make the compiler happy? I think the original .admin syntax is nicer

[samtstern]

Yeah it was ... do you have a suggestion for how we can have the . syntax? I actually don't mind this because it shows a division between types parts userRecord.customClaims and the any Danger Zone