EAS build fails at Install dependencies: Missing package from lock file

EAS builders npm 10.9.8 / Node 22; local npm 11 / Node 25; Expo SDK 57 (expo ~57.0.20, React Native 0.86.3, React 19.2.3)

npm error `npm ci` can only install packages when your package.json and package-lock.json are in sync. Missing: @shopify/flash-list@2.3.2 from lock file

Cause

EAS build images run npm 10, but the lockfile was written by npm 11. npm 11 leaves out some nested entries for optional or conflicting peers (here a nested peer of a chat SDK needing flash-list >=2.1.0) that npm 10's npm ci insists on. Local npm ci passes, EAS fails, and the EAS summary only says "Unknown error".

Fix

npx -y npm@10.9.8 ci --include=dev --dry-run

npx -y npm@10.9.8 install --package-lock-only

More npm errors

• EAS Install dependencies fails after adding a video SDK: deduped package below its peer range
• npm ci | tail reports exit 0 but the build still fails on install
• npx -y typescript@x tsc --noEmit prints no TS errors but did not typecheck at allcould not determine executable to run