package-managers

name	package-managers
description	Choosing the right JavaScript package manager and diagnosing install failures. Use before any install, add, or script command in a JS/TS repo, and when an install fails.

Package managers

1. The lockfile picks the manager. bun.lock/bun.lockb means bun, pnpm-lock.yaml means pnpm, yarn.lock means yarn, package-lock.json means npm. Never mix: running npm in a bun repo creates a second lockfile and a second dependency tree.
2. Run from the directory that owns the lockfile, not the repo root of a monorepo.
3. Scripts go through the owner. bun run build, pnpm run test; one-offs with bunx tool or pnpm dlx tool, never bare npx in a non-npm repo.
4. A failed install is not a reason to switch managers. If bun install fails, npm install in the same repo fails for the same underlying reason and leaves a mess behind. Diagnose the actual error instead.
5. Permission errors during installs are usually the sandbox. Writes are allowed in the repository, temp directories, and package caches (~/.npm, ~/.bun, ~/.cargo). An error naming another path means the sandbox blocked it; report the path instead of retrying.
6. Offline or turbo mode blocks the network. Installs need the network; say that plainly instead of retrying the install.