Advance your knowledge of callback-based APIs, callback behaviors and patterns in JavaScript. Learn & practise event loop, timers, async control flows, composition patterns, scoping, error handling, lazy evaluation, and many other relevant topics. Use latest ES6 features and functional helpers to make your code clean, safe, and modern. After this tutorial you'll be able to twist and bend any callback-based code like a true magician!



Callbacks (7 exercises)
Sync vs Async (12 exercises)
Queue priorities (4 exercises)
Think async (12 exercises)
Control flow (9 exercises)
Composition (7 exercises)
Error handling (13 exercises)
Integral (6 exercises)

70 exercises with solutions and explanations.

Before you start

1. We believe that a learning environment should be as realistic as possible. There are no Paste-n-Run sandboxes for coding tasks at Paqmind. You should use your own editor to write code and your own machine to run it – like a real pr...

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From the author

Sorry, couldn't resist a classic meme:

Now with all seriousness. We hear you asking "Do I even need to learn basic callbacks once there are Promises, Async-Await, Observables and newer stuff like that in JavaScript?! Aren't they...

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About the Author

Ivan Kleshnin
Fullstack Developer

Qualified engineer, mentor, and entrepreneur. 12+ years of experience. As an author, prefers to give universal knowledge that will remain relevant for years. Professional interests include functional and reactive programming, static types, software architecture.