Debug: npm ERR! ERESOLVE unable to resolve dependency tree

npm install fails with ERESOLVE error when packages have conflicting peer dependency requirements.

Diagnosis and fixes:

1. Read the error carefully - it shows which packages conflict:

npm ERR! peer dep A@^2.0.0 from B
npm ERR! peer dep A@^3.0.0 from C

1. Quick fix (npm 7+): --legacy-peer-deps

npm install --legacy-peer-deps
# Ignores peer dep conflicts (like npm 6 behavior)

1. Force install:

npm install --force
# Installs despite conflicts, may cause runtime issues

1. Proper fix: find compatible versions

npm ls <conflicting-package> # See current tree
npm view <package> peerDependencies # Check requirements
# Update packages to compatible versions

1. Use overrides in package.json (npm 8.3+):

{
"overrides": {
"conflicting-package": "^3.0.0"
}
}

1. Check if you can update the outdated package:

npm outdated
npm update <package>

1. Nuclear option: delete and reinstall

rm -rf node_modules package-lock.json
npm install