How to fix npm ERR! code ERESOLVE npm ERR! While resolving workspace dependencies in npm

Read the error output carefully—it shows exactly what conflicts:

npm ERR! ERESOLVE could not resolve
npm ERR! While resolving: [email protected]
npm ERR! Found: [email protected]
npm ERR! Could not resolve dependency:
npm ERR! peer react@"^18.0.0" from [email protected]

This tells you workspace-b needs react@18 but workspace-a has react@17.

The best fix is to use the same version everywhere. Update all workspace package.json files:

// packages/workspace-a/package.json
{
  "dependencies": {
    "react": "^18.0.0"
  }
}

// packages/workspace-b/package.json
{
  "dependencies": {
    "react": "^18.0.0"
  }
}

Or define shared dependencies in the root package.json.

Force all packages to use a specific version using overrides in root package.json:

{
  "overrides": {
    "react": "^18.2.0",
    "react-dom": "^18.2.0"
  }
}

Then reinstall:

rm -rf node_modules package-lock.json
npm install

This tells npm to use [email protected] regardless of what individual packages request.

Revert to npm 6's permissive behavior:

npm install --legacy-peer-deps

To make it permanent for the project, add to .npmrc:

legacy-peer-deps=true

Warning: This hides real conflicts that might cause runtime issues.

Force installation despite conflicts:

npm install --force

Warning: This can install incompatible versions and cause runtime errors. Only use when you understand the implications.

Move shared dependencies to the root package.json to ensure single versions:

// Root package.json
{
  "dependencies": {
    "react": "^18.2.0",
    "lodash": "^4.17.21"
  },
  "workspaces": ["packages/*"]
}

Workspaces automatically inherit root dependencies through hoisting.