TypeScript Best Practices for Clean, Maintainable Code

TypeScript shines when it helps you model reality — not when it forces you to fight types all day. A few small defaults can make a codebase feel calmer, safer, and easier to refactor.

Practical rules of thumb

• Turn on strictness and fix the sharp edges early.
• Prefer readable types over clever types.
• Use unions for “one of these”, interfaces for “shape of this”.
• Avoid any as a shortcut; it becomes future debt fast.

One pattern worth memorizing

type Result<T> =
  | { ok: true; value: T }
  | { ok: false; error: string };

export function parseNumber(input: string): Result<number> {
  const n = Number(input);
  return Number.isFinite(n) ? { ok: true, value: n } : { ok: false, error: "Not a number" };
}

Wrap-up

The best TypeScript code reads like good documentation: clear names, predictable shapes, and errors that point you to the fix.