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JavaScript

What is a npm Peer Dependency Conflict?

← Errors

npm throws a peer dependency conflict (ERESOLVE) when a package requires a specific version of another package that is incompatible with what is currently installed. npm v7+ treats unresolved peer dependencies as hard errors by default.

Why it happens

  • •A plugin or library requires a newer major version of a peer dependency than you have.
  • •Two packages in your dependency tree require conflicting versions of the same peer.
  • •Upgrading one package without upgrading its peers.
  • •A package has not been updated to support the latest major version of its peer.

Examples

JavaScript

Code that triggers the error

npm install some-plugin

Error output

npm warn ERESOLVE overriding peer dependency
npm error code ERESOLVE
npm error While resolving: some-plugin@2.0.0
npm error Found: react@17.0.2
npm error node_modules/react
npm error   react@"17.0.2"
npm error
npm error Could not resolve dependency:
npm error peer react@"^18.0.0" required by some-plugin@2.0.0

How to fix it

Upgrade your version of the peer dependency if possible. Pin to an older version of the package that supports your current stack. Use --legacy-peer-deps only as a last resort and test thoroughly. Use npm ls to visualize the dependency graph.

Fixed code

# Option 1: upgrade the peer dependency
npm install react@18

# Option 2: use legacy peer dep resolution (use with caution)
npm install some-plugin --legacy-peer-deps

# Option 3: use a version of the plugin compatible with your React version
npm install some-plugin@1.x

Related errors

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