I tried Flow and TypeScript out about half a year ago in a client project and Flow was kind of painful and difficult to use, the updates, bug fixes and new feat

I tried Flow and TypeScript out about half a year ago in a client project and Flow was kind of painful and difficult to use, the updates, bug fixes and new features weren't coming as often as TypeScript's were, and maybe 70% of people I talked to were using TypeScript instead of Flow. Since then it's more like 90% now, and the TS team seems to be adding and announcing features faster than before, whereas I haven't heard about any new features in Flow. Maybe they're there, I'm just saying I haven't heard about them. This is all anecdotal but from what I've heard, it's very common. This is a big reason I chose TypeScript in Autumn. Also, VS Code has become the de facto free editor of JavaScript projects with a full set of professional-grade IDE features across the board, and VS Code has first-class support for TypeScript but only plugin-level support for Flow. Since Monaco is simply extracted from VS Code, that means I got all VS Code's IDE features for free when I embedded Monaco into Autumn, all I had to do was set the language to "typescript" and it just works. All these free and serious benefits of TypeScript's ecosystem kind of point to this conclusion that I've seen on HN and elsewhere over and over, that TypeScript has already won and Flow is on its way out.