How Do You Tame the Async BEAST with Kotlin and JavaScript? - Sam Cooper

ACCU Membership: https://tinyurl.com/ydnfkcyn --- How Do You Tame the Async BEAST with Kotlin and JavaScript? - Sam Cooper --- Asynchronous programming can feel like taming a many-headed monster. In this talk from the ACCU York Meetup, Sam Cooper explores the central challenges of async control flow and how programming languages like JavaScript and Kotlin address them. Starting with callbacks and async/await in JavaScript, we uncover the pitfalls of diverging code paths, frozen UI threads, and hidden background tasks. Then, we explore how Kotlin coroutines and suspend functions offer a structured concurrency model that makes asynchronous programming more intuitive and manageable. By understanding the underlying structured programming problems, developers can use async tools effectively instead of memorizing a laundry list of rules. Key topics covered include: async await, callbacks, coroutines, Kotlin coroutines, suspend functions, structured concurrency, JavaScript async, concurrency, event loops, callbacks, parallel programming, and programming language design. Whether you're struggling with callbacks, trying to reason about async control flow, or looking to deepen your Kotlin and JavaScript concurrency knowledge, this talk provides actionable insights and clear explanations. Sam also references additional resources, including his books and articles on structured concurrency and asynchronous code design. Learn how to tame the many-headed async monster, improving both your JavaScript and Kotlin asynchronous programming skills while avoiding common pitfalls like hidden background tasks and diverging control flows. 0:05 – Introduction and book announcement 0:32 – Why write about asynchronous programming 1:02 – Challenges in Kotlin: coroutines, suspend functions, dispatchers 2:04 – Demonstrating async with JavaScript 2:44 – Structured programming principles 4:21 – Simulating delays and the problem with blocking 5:11 – Callbacks and non-blocking code 6:07 – Diverging control flow in asynchronous programming 8:01 – Pitfalls: try/catch, resource leaks, hidden tasks 10:05 – Async/await as a solution in JavaScript 12:03 – Benefits of async/await for control flow 13:30 – Limitations and hiding issues 14:00 – Kotlin suspend functions and safe async 15:04 – Managing background tasks in Kotlin 16:07 – Recommended reading and resources 17:01 – Runtime support, concurrency, and multi-threading 19:05 – Wrap-up and reflections on learning async --- Sam Cooper Sam Cooper is the author of Kotlin Coroutine Confidence and Kotlin Brain Teasers, both published by The Pragmatic Programmers in 2025. You'll also find his writing on Medium and in community publications such as Kotlin Weekly and Android Weekly. Sam's work on asynchronous programming in Kotlin has been cited in academic research and has influenced the evolution of Kotlin's coroutines library. --- ACCU The tagline for the ACCU is 'Professionalism in Programming', which captures the whole spectrum of programming languages, tools, techniques and processes involved in advancing our craft. While there remains a core of C and C++ - with many members participating in respective ISO standards bodies - the conference, like the organisation, embraces other language ecosystems and you should expect to see sessions on C#, D, F#, Go, Javascript, Haskell, Java, Kotlin, Lisp, Python, Ruby, Rust, Swift and more.The ACCU Conference is a conference by programmers for programmers about programming. Discounted rates for members. ACCU Membership: https://tinyurl.com/ydnfkcyn 2025 Program: https://accu.org/conf-previous/accu2025/ https://accu.org https://www.accuconference.org/ https://mastodon.social/@ACCUConf   / accu-conference   https://bsky.app/profile/accuconf.bsk...   / accuorg     / accuconf   --- YouTube Videos Edited & Optimised by Digital Medium: https://events.digital-medium.co.uk --- #accuconf #programming #cplusplus #coroutines #async #asynchronousprogramming #asyncprogramming