Node.js theorytheory 0/50 · 0%
Tooling · medium

21. Debugging Node applications

console methods, the inspector protocol, and node --inspect.

Beyond `console.log`, Node's console object has `console.table`, `console.time`/`console.timeEnd` for quick timing, and `console.error` which writes to stderr instead of stdout (important for separating logs from error streams in production).

js
console.time("fetch");
await fetchBalances();
console.timeEnd("fetch"); // fetch: 42.318ms

console.table([{ chain: "Base", id: 8453 }, { chain: "OP", id: 10 }]);

Running `node --inspect index.js` opens a debugging port that Chrome DevTools or VS Code can attach to, giving breakpoints, step-through execution, and a live REPL against the running process — far more powerful than scattering console.log calls through a large codebase.

Check your understanding

  1. 1. What flag lets you attach Chrome DevTools to a running Node process?

  2. 2. Where does console.error write by default?

  3. 3. What does console.time/timeEnd measure?