Duplicated type-checking of shared files in client and server bundles

[eliot-akira]

In a "universal" React project with client and server bundles, there are two Webpack compilers running. When a change is made in a file shared by both client and server - which is to say, most files - the same file is type-checked twice, since there are two Checker processes.

Ideally, if a file is alreadying being checked, the second Checker would ignore it.

I can understand if this is beyond the scope of atl, as it seems like a tough issue to solve. At the same time, I imagine there are many TypeScript+React projects with concurrent client/server bundles. It's not an "issue" per se, since I can just ignore the duplicated checker messages, but would be an improvement.