create-react-app 无法启动脚本后

Question

Failed at the start script and didn't run nothing, while running the following command:
npm start

The Error

There might be a problem with the project dependency tree.
It is likely not a bug in Create React App, but something you need to fix locally.

The react-scripts package provided by Create React App requires a dependency:

  "webpack-dev-server": "3.2.1"

Don't try to install it manually: your package manager does it automatically.
However, a different version of webpack-dev-server was detected higher up in the tree:

  /home/akhilbatchu/node_modules/webpack-dev-server (version: 3.8.1) 

Manually installing incompatible versions is known to cause hard-to-debug issues.

If you would prefer to ignore this check, add SKIP_PREFLIGHT_CHECK=true to an .env file in your project.
That will permanently disable this message but you might encounter other issues.

To fix the dependency tree, try following the steps below in the exact order:

  1. Delete package-lock.json (not package.json!) and/or yarn.lock in your project folder.
  2. Delete node_modules in your project folder.
  3. Remove "webpack-dev-server" from dependencies and/or devDependencies in the package.json file in your project folder.
  4. Run npm install or yarn, depending on the package manager you use.

In most cases, this should be enough to fix the problem.
If this has not helped, there are a few other things you can try:

  5. If you used npm, install yarn (http://yarnpkg.com/) and repeat the above steps with it instead.
     This may help because npm has known issues with package hoisting which may get resolved in future versions.

  6. Check if /home/akhilbatchu/node_modules/webpack-dev-server is outside your project directory.
     For example, you might have accidentally installed something in your home folder.

  7. Try running npm ls webpack-dev-server in your project folder.
     This will tell you which other package (apart from the expected react-scripts) installed webpack-dev-server.

If nothing else helps, add SKIP_PREFLIGHT_CHECK=true to an .env file in your project.
That would permanently disable this preflight check in case you want to proceed anyway.

P.S. We know this message is long but please read the steps above :-) We hope you find them helpful!

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! appnamsse@0.1.0 start: `react-scripts start`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the appnamsse@0.1.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/akhilbatchu/.npm/_logs/2019-11-14T06_22_13_747Z-debug.log

Here is the complete log about what happened:

0 info it worked if it ends with ok
1 verbose cli [
1 verbose cli   '/home/akhilbatchu/.nvm/versions/node/v12.13.0/bin/node',
1 verbose cli   '/home/akhilbatchu/.nvm/versions/node/v12.13.0/bin/npm',
1 verbose cli   'start'
1 verbose cli ]
2 info using npm@6.12.0
3 info using node@v12.13.0
4 verbose run-script [ 'prestart', 'start', 'poststart' ]
5 info lifecycle appnamsse@0.1.0~prestart: appnamsse@0.1.0
6 info lifecycle appnamsse@0.1.0~start: appnamsse@0.1.0
7 verbose lifecycle appnamsse@0.1.0~start: unsafe-perm in lifecycle true
8 verbose lifecycle appnamsse@0.1.0~start: PATH: /home/akhilbatchu/.nvm/versions/node/v12.13.0/lib/node_modules/npm/node_modules/npm-lifecycle/node-gyp-bin:/home/akhilbatchu/appnamsse/node_modules/.bin:/home/akhilbatchu/.nvm/versions/node/v12.13.0/bin:/home/akhilbatchu/anaconda3/bin:/home/akhilbatchu/anaconda3/condabin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin
9 verbose lifecycle appnamsse@0.1.0~start: CWD: /home/akhilbatchu/appnamsse
10 silly lifecycle appnamsse@0.1.0~start: Args: [ '-c', 'react-scripts start' ]
11 silly lifecycle appnamsse@0.1.0~start: Returned: code: 1  signal: null
12 info lifecycle appnamsse@0.1.0~start: Failed to exec start script
13 verbose stack Error: appnamsse@0.1.0 start: `react-scripts start`
13 verbose stack Exit status 1
13 verbose stack     at EventEmitter.<anonymous> (/home/akhilbatchu/.nvm/versions/node/v12.13.0/lib/node_modules/npm/node_modules/npm-lifecycle/index.js:332:16)
13 verbose stack     at EventEmitter.emit (events.js:210:5)
13 verbose stack     at ChildProcess.<anonymous> (/home/akhilbatchu/.nvm/versions/node/v12.13.0/lib/node_modules/npm/node_modules/npm-lifecycle/lib/spawn.js:55:14)
13 verbose stack     at ChildProcess.emit (events.js:210:5)
13 verbose stack     at maybeClose (internal/child_process.js:1021:16)
13 verbose stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:283:5)
14 verbose pkgid appnamsse@0.1.0
15 verbose cwd /home/akhilbatchu/appnamsse
16 verbose Linux 4.15.0-64-generic
17 verbose argv "/home/akhilbatchu/.nvm/versions/node/v12.13.0/bin/node" "/home/akhilbatchu/.nvm/versions/node/v12.13.0/bin/npm" "start"
18 verbose node v12.13.0
19 verbose npm  v6.12.0
20 error code ELIFECYCLE
21 error errno 1
22 error appnamsse@0.1.0 start: `react-scripts start`
22 error Exit status 1
23 error Failed at the appnamsse@0.1.0 start script.
23 error This is probably not a problem with npm. There is likely additional logging output above.
24 verbose exit [ 1, true ]

Versions :
Node: v12.13.0
NPM: v6.12.0

Environment
react: "^16.11.0",
react-dom: "^16.11.0",
react-scripts: "3.2.0"

Could anyone please help me as I am not able to figure out what is going wrong and completely new to react.

Thank you.

Answer 1

Have you installed the dependencies.

npm install

If it doesn't work delete the node_modules folder from project. then

npm install
npm start 

Answer 2

Did you read the first error message?

It says (step 6) you have (accidentally, probably) installed a copy of webpack-dev-server into your home directory

/home/akhilbatchu/node_modules/webpack-dev-server

Get rid of that copy (for instance, rename /home/akhilbatchu/node_modules into /home/akhilbatchu/node_modules_unused if you don't want to outright remove it), then try again.

Answer 3

I did followed this steps to work

1. npm install -g npm@latest it'll update npm, in case your modules are not updated

2. rm -rf node_modules

   Delete node_modules in your project folder. as mentioned in the log

3. npm install

   Run npm install or yarn, depending on the package manager you use. as it is mentioned in the console