[TS/JS] Allow --ts-flat-files and --gen-all to work in combination

[dbaileychess]

Currently these two flags cannot be used at the same time.

My idea is, for a given relationship:

foo.fbs

include "bar/bar.fbs";

a single foo_generated.ts is produced that

1. Doesn't have any imports (apart from flatbuffers runtime)
2. exports all types:

export class Bar {}
export class Foo {}

[dbaileychess]

@jkuszmaul Is this the expected out in this case?

[jkuszmaul]

@dbaileychess Yep. The main ambiguity is (I think) how to manage similarly named objects in different namespaces. I think the current --gen-all without --ts-flat-files handles this by prefixing type names with the fully qualified namespace if needed, but I'm not sure how well-defined that is.

foo.fbs

namespace foo;
include "bar.fbs"

table Foo {
  foo:int (id: 0);
}

bar.fbs

namespace bar;

table Foo {
  bar:string (id: 0);
}

Then you have two objects named Foo, and there's a legitimate question as to what name they should be exported as. I think if we replicated existing logic you'd end up with

foo_generated.ts

export class Foo {
  foo(): number {}
};

export class barFoo {
  bar(): string {}
};

[dbaileychess]

Thanks for the hint about namespacing.

Is barFoo what is preferred? What about bar_Foo or something?

[dbaileychess]

Ok, I am going to worry about the namespace aliasing in another issue, as I don't want to conflate the two.

[jkuszmaul]

I don't have strong feelings about the actual naming style. For consistency with how the non---ts-flat-files codegen works, I don't think you want the underscore. See, e.g., how it is handled with the overloaded Monster name in monster_test.ts:

flatbuffers/tests/monster_test.ts

Lines 1 to 7 in 2ad4086

	export { Monster as MyGameExample2Monster, MonsterT as MyGameExample2MonsterT } from './my-game/example2/monster';
	export { Ability, AbilityT } from './my-game/example/ability';
	export { Any, unionToAny, unionListToAny } from './my-game/example/any';
	export { AnyAmbiguousAliases, unionToAnyAmbiguousAliases, unionListToAnyAmbiguousAliases } from './my-game/example/any-ambiguous-aliases';
	export { AnyUniqueAliases, unionToAnyUniqueAliases, unionListToAnyUniqueAliases } from './my-game/example/any-unique-aliases';
	export { Color } from './my-game/example/color';
	export { Monster, MonsterT } from './my-game/example/monster';

The quibble I have with that approach is that it is not obvious to the user which name is likely to end up prefixed and which will show up cleanly.

[jkuszmaul]

And any discussion of how to manage these conflicts should go along with whatever #7448 does.

I'm also realizing that it would also be entirely consistent with the goals of both of the flags to have --gen-all --ts-flat-files generate multiple files, as long as it is still one per input file, which would avoid the whole namespacing issue. Although there is also utility in the "merge them all together into one" option.