Cannot find module react-scripts

[MrMYHuang]

Description

Fail to run create-react-app.cmd.

Expected behavior

create-react-app.cmd should create a react project without errors.

Actual behavior

PS D:\git> create-react-app.cmd r
Creating a new React app in D:\git\r.

Installing packages. This might take a couple minutes.
Installing react-scripts...

Error: Could not find or load main class add
module.js:472
throw err;
^

Error: Cannot find module 'D:\git\r\node_modules\react-scripts\package.json'
at Function.Module._resolveFilename (module.js:470:15)
at Function.Module._load (module.js:418:25)
at Module.require (module.js:498:17)
at require (internal/module.js:20:19)
at checkNodeVersion (C:\Users\myh\AppData\Roaming\npm\node_modules\create-react-app\index.js:225:21)
at C:\Users\myh\AppData\Roaming\npm\node_modules\create-react-app\index.js:179:5
at ChildProcess. (C:\Users\myh\AppData\Roaming\npm\node_modules\create-react-app\index.js:165:5)
at emitTwo (events.js:106:13)
at ChildProcess.emit (events.js:191:7)
at ChildProcess.cp.emit (C:\Users\myh\AppData\Roaming\npm\node_modules\create-react-app\node_modules\cross-spawn\lib\enoent.js:40:29)

Environment

1. npm ls react-scripts:
   D:\git
   -- (empty)
2. node -v: v7.4.0
3. npm -v: 4.1.1
4. Operating system: Windows 10 Enterprise 64-bit build 14393.576
5. Browser and version: Firefox 50.1.0
6. create-react-app: 1.0.2

[gaearon]

Run npm install in D:\git\r\.
It seems that npm failed for some reason.

[MrMYHuang]

Hi gaearon,
I tried. Unfortunately, I got nothing useful information.
This is the package.json generated by the failed run of create-react-app.cmd r
{
"name": "r",
"version": "0.1.0",
"private": true
}

A further npm install only generated an empty node_modules folder.

[gaearon]

I see, that’s frustrating. We need to add better error handling for npm failures.
In the meantime please copy and paste this into your package.json:

{
  "name": "r",
  "version": "0.1.0",
  "private": true,
  "devDependencies": {
    "react-scripts": "0.8.4"
  },
  "dependencies": {
    "react": "^15.4.2",
    "react-dom": "^15.4.2"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"
  }
}

Then run npm install.

Sorry for the trouble.

[MrMYHuang]

Hi gaearon,
npm install run well with the fixed package.json. However, npm start failed:

r@0.1.0 start D:\git\r
react-scripts start

Could not find a required file.
Name: index.html
Searched in: D:\git\r\public

npm ERR! Windows_NT 10.0.14393
npm ERR! argv "L:\nodejs\node.exe" "C:\Users\myh\AppData\Roaming\npm\node_modules\npm\bin\npm-cli.js" "start"
npm ERR! node v7.4.0
npm ERR! npm v4.1.1
npm ERR! code ELIFECYCLE
npm ERR! r@0.1.0 start: react-scripts start
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the r@0.1.0 start script 'react-scripts start'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the r package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! react-scripts start
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs r
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls r
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR! D:\git\r\npm-debug.log

[gaearon]

Right, my fault. I forgot it also calls an initialization script.

Really, the easiest way to fix it would be to run create-react-app again with a different folder. If npm exits successfully then it should work fine.

[MrMYHuang]

Hi gaearon,
I run create-react-app.cmd r2, but I still got error "Cannot find module ... react-scripts."

[gaearon]

OK, I think I understand the issue now.

You have something called yarn on your system which is a Java program.
Create React App thinks it is Yarn package manager and attempts to use it instead of npm.

This is the same issue as #1257. As a temporary workaround you can remove yarn from your path. I understand it’s inconvenient. Would you like to submit a PR for detection code to use yarnpkg instead as described here?

cc @fson

[MrMYHuang]

Hi gaearon,

You are right. There is a yarn of Hadoop in my path. Thank you.

Additionally, unfortunately, I have no idea at this time about how to differentiate yarn of yarnpkg from yarn of Hadoop.

[gaearon]

Additionally, unfortunately, I have no idea at this time about how to differentiate yarn of yarnpkg from yarn of Hadoop.

We should just use yarnpkg alias instead of yarn when feature detecting. This should be unambiguous enough.

[fson]

I can make a PR with the change to yarnpkg in a moment.