TypeScript as a language is fragmented into two languages

[canonic-epicure]

Hello,

I found it very discouraging, that TypeScript is currently fragmented into 2 languages. The 1st one is TypeScript itself and 2nd is TypeScript+declaration files. The program, valid in the 1st language, is not valid in the 2nd. This means, the TypeScript is a superset of TypeScript+declarations.

You can express more logic in TypeScript, however the TypeScript+declarations is a standard for distributing code (to avoid recompilation of the source files).

Despite being a well-known issue, this fragmentation is not documented anywhere, and TS development team does provide any feedback about it. It is a hushed up thing, nobody wants to talk about this.

This issue should at least be described in details, on the documentation website.

[canonic-epicure]

The solution is simple - a design decision should be made, that *.d.ts files should create exactly the same internal compilation data, as regular source files. For that, probably a different format of the declaration files is needed, *.d2.ts

Its very discouraging, when you have to spent hours, mingling your code (that compiles just fine in TypeScript), reducing type-safety, to make it work in the TypeScript+declarations language. In certain cases its not possible at all.

[RyanCavanaugh]

Duplicate #35822.