Typescript Best Practices

Teaches you to use TypeScript's type system to make invalid states impossible at compile time. You'll write discriminated unions instead of boolean soup, use branded types to prevent mixing up IDs, and enforce exhaustive switch statements with never checks. The Zod section is practical: schema as source of truth, safeParse for user input, parse at API boundaries. It assumes you know TypeScript syntax already and focuses on patterns that prevent bugs before runtime. If you're still writing types with a bunch of optional fields and crossing your fingers, this will change how you model data.