Limit the exposed API to necessary methods and types

[merlinnot]

Since we're working on a v3 release, it might be wise to revise the API of the library. Multiple types are exposed that seem not necessary, which might result in issues when internal structure of the library is modified (e.g. LegacyEvent).

It's also easier for developers when autocomplete suggests only usable types and it's not bloated with internals.

We should verify that all exported types actually belong to the API layer. This can be done by modifying the following:

firebase-functions/src/index.ts

Lines 55 to 57 in 18c01cb

	export * from './config';
	export * from './cloud-functions';
	export * from './function-builder';

in the following way:

export { Only, Necessary, Types } from './config';
export { No, Internals } from './cloud-functions';
export { Nice, And, Small } from './function-builder';

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[thechenky]

Internal bug reference: 135147671

[akauppi]

@merlinnot What happened to this? Chose to ask since you mention v3 and the library is now at 3.8.0.

[merlinnot]

No one had time to pick it up, or in other words, it was/is not a priority.

[inlined]

People probably weren't tracking a list of breaking changes to make on the next major version bump. I've created such a hotlist. We'll probably keep the export * from but will instead mark things that shouldn't be exported as @internal