Language Selection — TypeScript over JavaScript

Context

With Next.js selected as our frontend framework, we need to decide between JavaScript and TypeScript. Both are fully supported by Next.js.

Option	Pros	Cons	Fit
[[typescript]]	Catches bugs before runtime, powerful autocomplete, industry standard, types serve as documentation	Learning curve, compile step, config file needed	✅
JavaScript	No setup, shorter code, zero learning curve	Runtime bugs, weak autocomplete, falling behind in industry adoption	❌

TypeScript.

Primary reasons:

Industry standard — ~78% of JS developers use TypeScript (2025). Job postings list TypeScript, not JavaScript. For a portfolio targeting North American jobs, this matters.
Next.js defaults to it — create-next-app sets up TypeScript automatically. No extra configuration burden.
Gradual adoption — We can start writing JavaScript-style code in .tsx files and add types progressively. No need to learn advanced TypeScript upfront.
Portfolio signal — TypeScript in a portfolio project demonstrates awareness of production-grade practices.
Editor experience — Autocomplete and inline documentation make working with unfamiliar libraries much faster.

Learning overhead — TypeScript adds concepts (interfaces, generics, type narrowing) on top of JavaScript. Mitigated by starting with basic types and learning as needed.
Occasional type fights — Some third-party libraries have poor type definitions, requiring any escape hatches. Acceptable for a portfolio project.