Coffee-script was obviously always a fad. It basically traded legibility for ergonomics. Adding nothing of particular value to maintainability and longevity.
TypeScript otoh is just ES with types. It moves in the completely opposite direction, adding just enough syntax to get a proper type system in place (a pretty good one to boot).
If anything I would expect it’s syntax additions to be adopted as the standard and directly supported by runtimes. Despite static typing not being that useful for interpreters.
Unless runtimes will completely phase out es, focusing on wasm. (But that will take decades, so not really an either or thing)
TypeScript otoh is just ES with types. It moves in the completely opposite direction, adding just enough syntax to get a proper type system in place (a pretty good one to boot).
If anything I would expect it’s syntax additions to be adopted as the standard and directly supported by runtimes. Despite static typing not being that useful for interpreters.
Unless runtimes will completely phase out es, focusing on wasm. (But that will take decades, so not really an either or thing)