How to fix npm ERR! code EDEDUPE npm ERR! Could not dedupe dependencies in npm | DevErrors

How to fix "npm ERR! code EDEDUPE npm ERR! Could not dedupe dependencies"

1Clean reinstall

Start fresh with a new dependency tree:

bash

rm -rf node_modules package-lock.json
npm install

This often resolves conflicts that built up over time.

2Use --prefer-dedupe during install

Prevent duplicates from occurring:

bash

npm install --prefer-dedupe

This tells npm to prefer deduplication during installation.

3Check for duplicate packages

See what would be deduplicated:

bash

npm find-dupes

This shows duplicate packages without making changes.

4Use legacy peer deps

Relax peer dependency checking:

bash

npm dedupe --legacy-peer-deps

Or during install:

bash

npm install --legacy-peer-deps

5Use overrides for specific versions

Force a specific version of a problematic package (npm 8.3+):

json

{
  "overrides": {
    "problematic-package": "1.2.3"
  }
}

Then reinstall:

bash

rm -rf node_modules package-lock.json
npm install

6Update conflicting packages

Check which packages have conflicts:

bash

npm ls duplicate-package-name

Update packages that depend on outdated versions:

bash

npm update parent-package

How to fix npm ERR! code EDEDUPE npm ERR! Could not dedupe dependencies in npm