Node.js Code Review Patterns

Load these checks when source, runtime entrypoints, or package scripts establish Node.js execution, including JavaScript, TypeScript, CJS, and MJS. Apply TypeScript or CLI checks alongside them when relevant; a package.json alone does not distinguish server code from a browser build.

Read Review principles before applying these checks; it defines authority, applicability, evidence, and blocking criteria.

Synchronous I/O in Request Path

• Trace fs.readFileSync, fs.writeFileSync, execSync, or spawnSync to the active request/event-loop path and establish the blocking consequence or violated latency contract.
• Use async variants or fs/promises for work that must not block that path. Do not flag isolated startup/setup I/O solely because it is in a server file.