Javascript 文件导致 React (Typescript) 无法启动

Question

I have a React project with Typescript. One day I create a javascript file in src/ and then my React app failed to start on localhost. Any explanation about this would be appriciated.
Evironment : Node 16.13.1
Step to reproduce :

git clone git@github.com:manaclan/fun-pms-frontend.git
cd fun-pms-frontend
git checkout vinhngo

Inside package.json remove:

"@types/react-facebook-login": "^4.1.4"
"react-facebook-login": "^4.1.1"

Then npm install and npm start will notify that localhost:3000 failed to connect. Removing src/setupProxy.js will make the server start as normal

Answer 1

That's because JavaScript is not allowed in Typescript projects, you would need to modify your Typescript config, add the following flag to to the config file

--allowJs

Depending on the module bundler you probably also have to set the output directory for the transpiled Typescript files.