Folks who write JavaScript today might not remember a time when it was normal to write JS and ship the same files verbatim to end users. We’ve seen a Cambrian explosion of new syntax, new tools, and new ways to build applications using JavaScript in the last decade. Many of those features are now built into modern browsers, but static typing is one of the last Big New Ideas that hasn’t made it into mainline JavaScript.

We’re conditioned to expect there will be a compilation step between our source code and the code that runs in a browser. That forces many decisions about how we structure our projects and the kinds of tools we can use to deliver the software we write. Minimizing or eliminating the reasons why folks might need that build-the-code step between the code they write and the code their users run opens up doors and new ways of writing and delivering software, and that’s exciting!

Think, for instance, what would it take to get something like the TypeScript type checker in Chrome’s devtools? A first step would be to adopt the type annotation syntax.