The npm EUSAGE error indicates a usage mistake or configuration mismatch in your npm command. Most commonly caused by misaligned package.json and package-lock.json files, this error prevents dependency installation during builds.
The npm EUSAGE error code stands for 'Error Usage' and signals that npm detected an incorrect usage of a command or a validation failure in your project configuration. This error typically occurs when npm's strict validation rules aren't met, such as when your package.json and package-lock.json files are out of sync, when lock files are missing or corrupted, or when command syntax is invalid. Unlike runtime errors in your code, EUSAGE errors indicate a problem with how npm itself is being invoked or how your project dependencies are configured. This error is most frequently encountered in continuous integration environments, automated deployments, and when using `npm ci` (clean install) which enforces strict validation.
Delete the package-lock.json file from your project and regenerate it by running npm install. This ensures your lock file matches your package.json exactly and was created with your current npm version.
# Remove the lock file and node_modules
rm -rf package-lock.json node_modules
# On Windows:
del package-lock.json
rmdir /s /q node_modules
# Reinstall dependencies
npm installThis creates a fresh package-lock.json that's synchronized with your package.json. Commit this updated lock file to your repository.
Ensure your package.json is valid JSON and your package-lock.json has the correct lockfileVersion. The lockfileVersion should be at least 1 for npm@5+.
# Validate package.json syntax
cat package.json | jq empty
# Check lock file version
grep -A 1 '"lockfileVersion"' package-lock.jsonIf you see lockfileVersion: 0 or missing, delete and regenerate the lock file. If package.json validation fails (jq error), check for trailing commas or missing quotes.
While npm ci is stricter and preferred in CI/CD, you can temporarily use npm install to work around EUSAGE errors. This is a workaround, not a permanent fix.
# Instead of:
npm ci
# Try:
npm installNote: npm ci is recommended for production builds because it enforces exact dependency versions. Only use npm install as a temporary workaround while you fix the underlying lock file issue.
Ensure you're using compatible versions of npm and Node.js. Older npm versions may not recognize newer lock file formats, causing validation errors.
# Check current versions
node --version
npm --version
# Update npm to latest stable (requires Node.js 12.13.0+)
npm install -g npm@latest
# Or use a specific version
npm install -g npm@9For CI/CD environments, update your GitHub Actions, Docker, or deployment platform to use Node.js 18+ and npm 8+.
For monorepo projects using npm workspaces, EUSAGE errors often stem from workspace configuration. Ensure all workspace package.json files have consistent dependency versions and that lock file entries reference correct workspace paths. In Docker deployments, the EUSAGE error frequently occurs when lock files are .dockerignore'd but required by npm ci. Always include package-lock.json in your Docker build context. On Windows systems using PowerShell, some users report EUSAGE with npm deprecate commands; switching to Command Prompt resolves the issue.
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