React Typescript: Line 0: Parsing error: Cannot re

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?

---

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

Just update typescript version to 3.8.x : Link

Answer 2

I case of an app generated by

npx create-react-app my-app --template typescript

More precisely, create-react-app@3.4.1

The issue was solved by running the following command:

rm yarn-lock && rm -rf node_modules && npm i

After which you may run:

either yarn start or npm start

Answer 3

In my case, the culprit was asset imports of non-existing files, e.g.:

import { ReactComponent as SomeIcon } from '../assets/img/some-icon.svg';

The answers above helped me find the culprit. I ran rm -rf node_modules package-lock.json && npm i && npm start, which caused the real errors to be shown (instead of the unhelpful cryptic "Line 0: Parsing error: Cannot read property 'name' of undefined")

Once I added the missing files, the errors went away.

Answer 4

The problem apparently was caused by a misconfiguration of some (peer?) dependencies of a dependeny, 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.

Answer 5

In my case, I just had to add an extra newline at the end of the ts file.

export * from './result';
export * from './request';
//new line here