React Typescript: Line 0: Parsing error: Cannot read property 'name' of undefined

Question

Today suddenly I started to get build errors on a project built with Typescript. In a file that (or anything it references) hasn't been changed in weeks, I started to get:

./path/to/my/file.ts   Line 0:  Parsing error: Cannot read property 'name' of undefined 

This error first appeared on our CI, could be replicated by manually building on the server, and I could finally reproduce on my own computer (which was running perfectly) after updating all packages. Now, even if I pull the old (building) commit of my project, I can't build it. I've got yarn.lock commited to my repo, but even with the old package.json and yarn.lock (I delete node_modules and do yarn), I can't build.

This error literally started out of blue today.

What could be the reason?

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My (possibly relevant) versions:

yarn 1.22.4, node v13.11.0, typescript 3.7.5 react 16.12 react-scripts 3.4.0 macOS 10.15 Catalina 

Answer 1

The problem apparently was caused by a misconfiguration of some (peer?) dependencies of a dependency, react-scripts with the TypeScript template. It went away. Make sure you update your dependencies, purge node_modules, even purge package-lock.json or yarn.lock, and try a fresh build again now.