Error when running npm start after create-react-app

[tskxz]

I am encountering an issue when trying to start a new React app using create-react-app. After running the commands below, I get the following error when executing npm start.

npx create-react-app client
cd client
npm start

The npm start command fails with the following error message:

> client@0.1.0 start
> react-scripts start

Cannot find module 'ajv/dist/compile/codegen'
Require stack:
- /home/tanjil/stockmaster/client/node_modules/ajv-keywords/dist/definitions/typeof.js
- /home/tanjil/stockmaster/client/node_modules/ajv-keywords/dist/keywords/typeof.js
- /home/tanjil/stockmaster/client/node_modules/ajv-keywords/dist/keywords/index.js
- /home/tanjil/stockmaster/client/node_modules/ajv-keywords/dist/index.js
- /home/tanjil/stockmaster/client/node_modules/schema-utils/dist/validate.js
- /home/tanjil/stockmaster/client/node_modules/schema-utils/dist/index.js
- /home/tanjil/stockmaster/client/node_modules/webpack-dev-server/lib/Server.js
- /home/tanjil/stockmaster/client/node_modules/react-scripts/scripts/start.js

[GustavoKasaki]

I got this error as well, where I solved by installing 'ajv' in dev dependencies:

npm install --save-dev ajv

#13643 (comment)

[Forlk4]

This often happens in projects created with older versions of create-react-app or when new versions of incompatible dependencies are automatically installed. I previously used the following method

1. Clean up old conflicting packages.

rm -rf node_modules
rm package-lock.json
npm cache clean --force

2. Manually add a compatible version of ajv (v6.x, because CRA uses that version).

npm install --save-dev ajv@6 ajv-keywords@3