npm ERR! code ERESOLVE

The npm ERR! code ERESOLVE error means npm found a peer dependency conflict. Fix it with --legacy-peer-deps, --force, or by updating conflicting packages.

What It Means

ERESOLVE is npm’s peer dependency resolution error, introduced in npm v7. When package A declares a peer dependency on a specific version of package B, and another package in your project requires a different (incompatible) version of B, npm refuses to proceed. The error message lists every conflicting package path.

Why It Happens

• Two packages in your project require different major versions of the same peer dependency.
• A package’s peerDependencies specifies a range (e.g., ^17.0.0) but the installed version is outside that range.
• Upgrading a framework (e.g., React 17 → 18) breaks peer dependency contracts for plugins still targeting the old version.
• Lockfile (package-lock.json) is out of sync with the dependency tree.

How to Fix It

1. Use --legacy-peer-deps (quick workaround)

npm install --legacy-peer-deps

This tells npm to ignore peer dependency conflicts (reverting to npm v6 behavior). It’s a good temporary fix but may lead to runtime issues.

2. Use --force (alternate workaround)

npm install --force

This forces npm to proceed, overwriting conflicting packages. Use only when --legacy-peer-deps doesn’t work.

3. Update the conflicting packages

Identify the exact conflict from the error output, then update the packages:

npm update react react-dom       # update framework packages
npm install react-select@latest  # update a plugin to a version compatible with your React version

4. Check and dedupe the dependency tree

npm ls                            # view the full dependency tree
npm dedupe                        # deduplicate identical packages

5. Clean install from scratch

rm -rf node_modules package-lock.json
npm install

A fresh install often resolves resolution state corruption in the lockfile.

6. Use overrides (package.json)

Add an overrides field to your package.json to force a specific version:

{
  "overrides": {
    "react": "18.3.1"
  }
}

Then run npm install again.