Development server error when proxy configuration is added to package.json

[dxataclub]

Discussed in #11788

^{Originally posted by petal-person December 16, 2021}
Platform: Ubuntu
Cra & react-scripts Version: 5.0.0
NodeJS Version: v16.13.1
NPM Version: 8.3.0

Okay so, whenever I add the proxy configuration to my package.json I get an error. But without it, the project compiles & the server starts just fine.

This is the terminal with the error:

> app@0.1.0 start
> react-scripts start

Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
 - options.allowedHosts[0] should be a non-empty string.

This even happens on a plain boilerplate project. this is what my package.json looks like:

{
  "name": "app",
  "proxy": "http://localhost:3001", //the error only occurs when this is here..
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.16.1",
    "@testing-library/react": "^12.1.2",
    "@testing-library/user-event": "^13.5.0",
    "react": "^17.0.2",
    "react-dom": "^17.0.2",
    "react-scripts": "5.0.0",
    "web-vitals": "^2.1.2"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }
}

I'm trying to figure out what the problem is, I don't know if it's with my server or something in react...

Any help is appreciated :)

[raix]

@petal-person thanks for reporting the issue, seems like we have an issue in the WDS configuration in some cases, closing this in favor of #11762