After creating a react app with 'create-react-app' things have been successful till now. I have made a working react project. But now that I'm looking to implement unit testing with jest.

Using npm to install: 'npm install --save-dev jest' Then running: npm ls jest I notice that the react-script is looking for a jest version that is significantly older.

package.json:

"dependencies": {
"react": "^16.8.1",
"react-dom": "^16.8.1",
"react-redux": "^6.0.0",
"react-scripts": "2.1.5",
"redux": "^4.0.1"
},

"devDependencies": {
"jest": "^24.7.1"
},

"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "jest",
"eject": "react-scripts eject"
}

npm ls jest result:

+-- [email protected]
`-- [email protected]
  `-- [email protected]

npm start 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:

"jest": "23.6.0"

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

C:\Users\userName\sample js codes\redux\songs\node_modules\jest (version: 
24.7.1)

Is there a solution to solve this dependency version issue?

After creating a react app with 'create-react-app' things have been successful till now. I have made a working react project. But now that I'm looking to implement unit testing with jest.

Using npm to install: 'npm install --save-dev jest' Then running: npm ls jest I notice that the react-script is looking for a jest version that is significantly older.

package.json:

"dependencies": {
"react": "^16.8.1",
"react-dom": "^16.8.1",
"react-redux": "^6.0.0",
"react-scripts": "2.1.5",
"redux": "^4.0.1"
},

"devDependencies": {
"jest": "^24.7.1"
},

"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "jest",
"eject": "react-scripts eject"
}

npm ls jest result:

+-- [email protected]
`-- [email protected]
  `-- [email protected]

npm start 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:

"jest": "23.6.0"

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

C:\Users\userName\sample js codes\redux\songs\node_modules\jest (version: 
24.7.1)

Is there a solution to solve this dependency version issue?

• javascript
• node.js
• reactjs
• jestjs

• As far as I know, create-react-app es with Jest built-in, no need to install it additionally. You have a version conflict now because you installed it additionally. Revert the package.json, that should fix it – Patrick Hund Commented Apr 11, 2019 at 11:24
• 1 You are absolutely correct. You are a wizard, Harry! – kevin man Commented Apr 11, 2019 at 12:35

1 Answer 1

Create-react-app es with Jest built-in, there is no need to install it additionally.

You have a version conflict now because you installed it additionally. To fix it, revert your changes to package.json.