Securing npm dependencies: Best practices for Safe JavaScript development¶
The npm registry hosts millions of packages, making it both incredibly useful and potentially dangerous. Malicious packages, accidental secret leaks, and vulnerable dependencies can compromise your entire application. Here’s how to use npm safely.
Key practices for secure npm usage¶
Prevent secret leaks
Double-check ignore files:
Keep
.npmignorein sync with .gitignoreBetter yet, use the files property in
package.jsonas a whitelist (The files property takes precedence over.npmignore):
{
"files": ["dist/", "lib/", "index.js"]
}
Always do a dry run before publishing:
npm publish --dry-run
Lock down dependencies
Enforce deterministic installs to ensure everyone gets the exact same dependency tree:
npm ci # For npm (uses package-lock.json)
yarn install --frozen-lockfile # For Yarn
Reduce Attack Surface
Be cautious with updates:
Wait a few days before adopting new major versions
Always review changelogs and GitHub issues first
Disable potentially dangerous scripts:
npm install --ignore-scripts
Or add to .npmrc: ignore-scripts=true
Maintain project health
Check for outdated packages:
npm outdated
Verify your npm environment:
npm doctor
This checks:
Registry connectivity
Git availability
Version compatibility
Filesystem permissions
Audit Dependencies Regularly
Use built-in tools:
npm audit
For deeper scanning:
npx snyk test
Snyk provides:
More comprehensive vulnerability detection
Continuous monitoring
Better remediation guidance
npm Security Checklist¶
Prevent leaks: Use files whitelist + dry runs
Lock dependencies: Use npm ci or –frozen-lockfile
Update carefully: Review changelogs before upgrading
Disable scripts: –ignore-scripts in installs
Check health: Regular npm outdated and npm doctor runs
Audit dependencies: Combine npm audit with Snyk
When things go wrong¶
Found a malicious package? Report to npm security: security@npmjs.com
Vulnerable dependency? Check Snyk’s remediation advice