Client-side programming is asynchronous by nature, as changes to UI state are prompted by user events, network responses, etc. The most common ways of handling events are:

• callback functions (used to be the only way, e.g. via addEventListener),
• Promises (now built into ECMAScript, including async/await syntax),
• Observable pattern (more expressive, currently reliant on 3rd party implementations, e.g. RxJS).

Promises

📖 Documentation

• constructing new Promises
• handling Promises:
  • .then and .catch
  • async/await
• Promise synchronization

RxJS

📖 Documentation

• official docs
• RxJS operators
• RxJS Subjects
• RxJS marbles

🎥 Courses

• Reactive JS: Are you ready for the next big paradigm shift? - Udemy course (ask for credentials)

💬 Talks

• You don't need RxJS ... but it f**king helps by Pavel Tobiáš (PDF slides, source code)

🔨 Workshops

• RxJS operators and observable chain by Jan Strapek (Google slides, PDF)