Bun API Review

Review code and flag issues in two categories: Node.js APIs that have Bun-native replacements, and incorrect usage of Bun APIs.

Node.js to Bun Replacements

Flag these Node.js patterns and suggest the Bun native equivalent:

Node.js Pattern	Bun Native	Why
fs.readFile / fs.writeFile	Bun.file().text() / Bun.write()	10x faster, no callback overhead
node:http / node:https server	Bun.serve()	Built-in, faster, simpler API
express / koa / fastify	Bun.serve() + Hono or Elysia	Bun-optimized frameworks
node-fetch / undici	Native fetch	Built into Bun runtime
dotenv	Native .env loading	Bun loads .env automatically
bcrypt / bcryptjs	Bun.password.hash() / .verify()	Native, no C bindings needed
jest / vitest	bun:test	Built-in test runner
child_process.spawn	Bun.spawn() / Bun.$ shell	Simpler API, better perf
ws (WebSocket lib)	Bun.serve() websocket option	Built-in WebSocket server
crypto.randomUUID()	Bun.randomUUIDv7()	Sortable, better for DB keys
node:path.resolve	Bun.resolveSync()	Module resolution
sqlite3 / better-sqlite3	bun:sqlite	Built-in, zero-copy
glob / fast-glob	Bun.Glob	Native, faster
chalk / picocolors	Bun.color()	Built-in ANSI color support

Bun API Correctness

Flag these common mistakes:

• Bun.file(): Must call .text(), .json(), .arrayBuffer(), or .stream() to actually read — the BunFile object is lazy
• Bun.serve(): Must store the return value if you need to call .stop() or .reload() later
• Bun.write(): Second arg can be string, Blob, BunFile, or Response — don't unnecessarily convert to string first
• Bun.spawn(): Use Bun.$ (shell) for simple commands; use Bun.spawn() for streaming or fine-grained control
• bun:sqlite: Use .prepare() for repeated queries — don't call .query() in loops
• bun:test: Use expect().toEqual() for deep equality, not toBe() on objects
• Hot reload: Use Bun.serve({ development: true }) in dev, not nodemon/ts-node-dev

Out of Scope

Don't flag:

• General TypeScript quality (typing, formatting) — that's for a TS standards skill
• Business logic or architecture decisions
• Node.js APIs that Bun doesn't have native replacements for (these are fine via Node.js compat)