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TypeScript & Node.js · Developer Error Resolution Lab

Fix NPM Error: 'ERESOLVE unable to resolve dependency tree' (Peer Dependencies)

Resolve strict peer dependency conflicts in npm 7+ using --legacy-peer-deps or updating outdated packages.

Triggered Error Message:

npm error code ERESOLVE npm error ERESOLVE unable to resolve dependency tree

Customize Solution for Your Environment
# Option 1: Temporary bypass (recommended for peer conflicts):
npm install package-name --legacy-peer-deps

# Option 2: Persist in project (.npmrc file):
echo "legacy-peer-deps=true" >> .npmrc

# Option 3: Check conflicting dependency tree:
npm ls react

Root Cause & Mechanism Analysis

Why does this error occur?

npm v7+ installs peer dependencies by default. If package A requires React 18, but package B requires React 19, npm halts with an ERESOLVE conflict.

Frequently Asked Questions

What does --legacy-peer-deps do?
It tells npm to ignore conflicting peerDependencies, adopting npm v4-v6 behavior.

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