Emit 'export as namespace ts' in our bundled d.ts output

[jakebailey]

I was reading https://johnnyreilly.com/definitely-typed-the-movie and saw the export as namespace syntax, which triggered a memory that made me remember that we used to have this in our output pre-modules, but I did not preserve it.

Before, we had:

• typescript.d.ts, which only had export = ts
• tsserverlibrary.d.ts, which had both export = ts and export as namespace ts.
• typescriptServices.d.ts, which just declared the ts namespace without exporting it.

Given we still let ts be loaded on the globals if not in CJS, this seems like it's correct to say that there's a global ts namespace when not imported.

[fatcerberus]

Wait, typescript.d.ts and typescriptServices.d.ts were different despite that the corresponding .js files were identical?

[jakebailey]

Yes, yes they were!

[jakebailey]

@DanielRosenwasser I stuck this in 5.0.3 as this feels like something we should backport for the patch release?

Not totally sure how to test that this doesn't negatively impact anyone but I'm pretty sure it does not.

[DanielRosenwasser]

I'm confused, didn't we say these files shouldn't contain an export as namespace in chat?

[jakebailey]

I think we started with "nobody's complaining, so why bother", but Andrew (and I, originally) seemed to think that if the output file would put itself into the globals when not loaded via an import that it should declare so.

[jakebailey]

We're like 10 months post-module migration; given nobody has complained about this I'm just going to close this. If we ever want to change that, we can still revive this, but I really suspect anyone who wants us in a browser is just bundling anyhow.