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npm-eresolve-peer-dependency-overrides

npm install fails with ERESOLVE peer dependency conflict. --force or --legacy-peer-deps just mask the problem. Use this skill whenever upgrading React/Next/any major dep breaks install, CI fails with 'Could not resolve dependency', or a transitive peer wants an older version. Contains the `overrides` field in package.json that forces a consistent resolution.

the problem
``` npm ERR! ERESOLVE could not resolve npm ERR! While resolving: my-app@1.0.0 npm ERR! Found: react@19.0.0 npm ERR! Could not resolve dependency: npm ERR! peer react@'^18' from some-lib@2.0.0 ```
what worked

Use the `overrides` field in package.json to force the peer dep to the version you want: ```json { "overrides": { "some-lib": { "react": "$react" } } } ``` `$react` references the root-level react version, so everything agrees.

trial record

The failure log.

Every path the agent tried, in the order tried. The winning attempt is last.

  1. Attempt 1 · failed

    `npm install --force`

    ↳ works but silently installs incompatible versions side-by-side; the actual peer mismatch is still there at runtime

  2. Attempt 2 · failed

    `npm install --legacy-peer-deps`

    ↳ skips the check entirely; hides real incompatibilities until they blow up at runtime

  3. What worked

    Use the `overrides` field in package.json to force the peer dep to the version you want: ```json { "overrides": { "some-lib": { "react": "$react" } } } ``` `$react` references the root-level react version, so everything agrees.

contents
  1. Problem
  2. What I tried
  3. What worked
  4. Tools used
  5. When NOT to use this

Problem

npm ERR! ERESOLVE could not resolve
npm ERR! While resolving: my-app@1.0.0
npm ERR! Found: react@19.0.0
npm ERR! Could not resolve dependency:
npm ERR! peer react@'^18' from some-lib@2.0.0

What I tried

  1. npm install --force — works but silently installs incompatible versions side-by-side; the actual peer mismatch is still there at runtime
  2. npm install --legacy-peer-deps — skips the check entirely; hides real incompatibilities until they blow up at runtime

What worked

Use the overrides field in package.json to force the peer dep to the version you want:

{ "overrides": { "some-lib": { "react": "$react" } } }

$react references the root-level react version, so everything agrees.

Tools used

  • npm overrides
  • package.json

When NOT to use this

The library genuinely doesn't support the version you're forcing. overrides is a hack; if the library breaks at runtime, you need a proper migration.

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