Perhaps one day I will. When I last started a big JS project it wasn't mature enough to build a company around. This does seem to be changing.

TypeScript is awesome compared to JavaScript and even to other popular C-like languages. But it inherits all of the problems of the JS ecosystem without providing all of the benefits.

To make a JS package consumable by a reasonably strict TS project, someone has to basically rewrite the package. It's less effort than writing one from scratch, but it's not free.

> To make a JS package consumable by a reasonably strict TS project...

I’m not sure what you mean by “strict” here... Certainly one can use JavaScript from TypeScript, and even provide type information for the JS with declaration files. [1] Does a “strict” project require something beyond this?

[1] “Declaration Files”, TypeScript Handbook https://www.typescriptlang.org/docs/handbook/declaration-fil...

Type information is easy to half-ass: list all the exports, mark them as 'string', 'Object', 'Function', done.

Adding the actually correct and reliable types is the hard part. (But easier than writing the code in the first place.)

The typescript compiler can be a bit slow at times as well which dramatically lowers the developer experience when using typescript