This is not at all my area of expertise, so take my opinion with a grain of salt. That being said, Javascript Flow seems like a better solution than Typescript.

This is not at all my area of expertise, so take my opinion with a grain of salt. That being said, Javascript Flow seems like a better solution than Typescript. Long term, a sandboxed low-level VM like WebAssembly will hopefully catch on and allow web devs to replace all of these not-quite-javascript languages.