TypeScript’s new isolated declaration feature is a game changer for packaging and distributing JavaScript code. It eliminates the need to manually create *.d.ts files, making the process significantly faster and simpler. By allowing tools other than the TypeScript compiler to generate .d.ts files from TypeScript source code, developers can now easily publish their code without the hassle of dealing with complex build artifacts. This revolutionary feature has been implemented in Deno since December 2023, making packaging code a breeze for all users. With JSR registry, developers can now generate .d.ts files on the fly, transforming the way we share code among developers.
https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-10/