Day 1/90: TypeScript setup and first types

90 Day TypeScript Challenge: Zero to Production

Today I wanted typescript setup and first types to feel like a real engineering decision, not a syntax demo. The useful shift was setting the project up so the compiler catches the first real mistake quickly.

The checks that mattered were turn strictness on for a reason and know which category of bug each flag is buying down, separate source layout, build output, and path aliases before the project gets busy, and keep the toolchain small enough that a new teammate can explain it without opening six config files.

The failure mode I was actively trying to avoid was treating tsconfig like a bag of copied defaults instead of engineering policy. That is usually the moment a typed codebase starts looking safe while still carrying fuzzy contracts underneath.

On setup days I care less about Hello World and more about whether the repo will fail fast once real code lands.

That is the bar I want from the track: code that stays readable when requirements move, not just code that compiles today.