01 · React / TypeScript
JavaScript: your first program
Run a JavaScript file and understand the difference between a browser and Node.js.
54 Tutorials · DE / EN
Learn to code: React / TypeScript
Start with no prior knowledge. Small examples explain the language. Medium guides connect building blocks. Large tutorials walk through complete project workflows.
React / TypeScript
Small
02 · React / TypeScript
Variables and data types in JavaScript
Use const and let and identify text, numbers, booleans and missing values.
03 · React / TypeScript
Operators, comparisons and if
Choose between workflows based on a condition.
04 · React / TypeScript
Loops in JavaScript
Iterate over values and calculate a total.
05 · React / TypeScript
Functions and scope
Write reusable calculations and understand local variables.
06 · React / TypeScript
Arrays, objects and new values
Describe records and create changes without overwriting the old value.
07 · React / TypeScript
HTML and CSS: the foundation of a web interface
Open a simple web page and separate content from styling.
08 · React / TypeScript
TypeScript types and modules
Describe allowed data shapes and check them before execution.
09 · React / TypeScript
Promises, async/await and errors
Wait for eventual results and handle failed tasks.
Medium
10 · React / TypeScript
First React app: JSX, props and state
Render components and change state through a user action.
11 · React / TypeScript
Forms, lists and effects
Validate forms and deliberately synchronise with an external browser function.
12 · React / TypeScript
React Native, Expo and navigation
Apply React foundations to mobile views and understand native boundaries.
13 · React / TypeScript
SQLite and repositories in House Log
Understand local SQL persistence, transactions and separate device adapters.
14 · React / TypeScript
HTTP contracts and runtime validation
Distinguish transport failures, HTTP failures and invalid response data.
15 · React / TypeScript
Test components and repositories meaningfully
Verify a user action and identify failures only real database tests can find.
Large
16 · React / TypeScript
A small offline house log with React Native
Connect native input, a service and a SQLite repository replaceable between Android and tests.
17 · React / TypeScript
Persistent optimistic UI, replay and conflicts
Persist intent before sending and prevent duplicate effects when a response is lost.
18 · React / TypeScript
Shared editing with WebSockets and PostgreSQL
Understand ordered operations, reconnection and a durable operation log’s role.