Build Tools — Senior Interview Prep
Bundlers, transformers, monorepo tools, package managers — the parts of the frontend build chain a senior is expected to understand and tune. Not “how do I configure Webpack” line-by-line — what each tool is for, what it trades, and when to pick which.
Files
The decision cheat sheet
| Decision | Default answer (2026) | When to deviate |
|---|---|---|
| Bundler for a new app | Vite | existing Webpack config / Next.js (Turbopack) / React Native (Metro) |
| Transformer | SWC (Vite/Next.js default) or esbuild (Vite dev) | need a Babel plugin no SWC equivalent exists for |
| Package manager | pnpm | npm if it’s the team’s strong preference, yarn for legacy |
| Monorepo runner | Turborepo for simple, Nx for opinionated/structured | Lerna is legacy |
| Lockfile | always commit | one source of truth per repo |
| Module format you ship | ESM with CJS fallback via exports map |
library only — apps don’t ship |
Cross-references
- Bundle analysis / code splitting strategy: Bundle Analysis and Code Splitting
- Tree shaking (depends on bundler): Tree Shaking — How It Actually Works, What Defeats It
- Project structure (monorepo layout): Project Structure — Senior Interview Prep