What is the language baseline for RN?
React Native is JavaScript, and in 2026 effectively TypeScript. Before the mobile-specific parts make sense, you need solid modern JS — async, modules, destructuring — and enough TypeScript to type props and state. This is the foundation the rest of the track stands on.
Why it matters
Most struggles early in React Native are really JavaScript or TypeScript gaps,
not mobile gaps. Confusion about async, this, or types shows up as baffling
mobile bugs. Getting the language solid first means the mobile concepts land
cleanly instead of compounding confusion.
What to learn
- Modern JS: arrow functions, destructuring, spread, modules
- Promises and async/await
- Array methods: map, filter, reduce
- TypeScript basics: types, interfaces, generics
- Typing component props and state
- Optional chaining and nullish coalescing
- Reading TypeScript errors
Common pitfall
Skipping TypeScript to "move faster," then drowning in runtime errors that types would have caught at build time — a wrong prop shape, an undefined value, a misspelled field. On mobile those errors crash the app on a device. Type your components from the start; it is faster overall, not slower.
Resources
Primary (free):
- javascript.info · docs
- TypeScript — Handbook · docs
- React Native — TypeScript · docs
Practice
Write a small TypeScript module: a typed function that fetches data with async/await, transforms it with map and filter, and a typed interface for the result. Trigger a type error by passing the wrong shape and read it. Done when your code is fully typed and the compiler catches a deliberate mistake.
Outcomes
- Use modern JavaScript and async/await fluently.
- Type functions, props, and state with TypeScript.
- Transform data with array methods.
- Read and fix TypeScript errors.