IntermediateTopic 44 of 104Software & Computing
Asynchronous programming
Non-blocking I/O with callbacks, promises and async/await.
In depth
Asynchronous code starts operations and continues without blocking, resuming when results arrive: callbacks, promises/futures, async/await, event loops (Node.js, asyncio). Ideal for I/O-bound work (network, disk) and UIs. Errors and cancellation need careful handling.
Key points
- Event loop
- Callback hell
- Concurrency without threads
Exampleawait fetch(url) pauses the function while the event loop serves other tasks.
What is Asynchronous programming?
Non-blocking I/O with callbacks, promises and async/await.
Why is it important to understand asynchronous programming?
Asynchronous programming lets a program wait for slow operations without blocking, which is needed for web servers and user interfaces.
What does async/await do?
It lets code that waits for an operation read like normal sequential code, while the program continues to run other work during the wait.
What is a callback?
A function passed to another function to run when an operation finishes, which can lead to deeply nested code if not managed.
How is Asynchronous programming used in practice?
Typical applications include fetching data from several web services at once without freezing the page, reading from a serial port while updating a display and handling many client connections in a server without a thread for each.
What should I learn before Asynchronous programming?
Study "Race conditions and deadlocks" first (topic 43 of 104 in Software & Computing). It covers the groundwork this topic builds on.
What are the key points of Asynchronous programming?
Event loop. Callback hell. Concurrency without threads.
Can you give an example of Asynchronous programming?
await fetch(url) pauses the function while the event loop serves other tasks.
What comes after Asynchronous programming?
The next topic is "Software development life cycle", which builds directly on this one.
How difficult is Asynchronous programming?
It is classed as Intermediate in Software & Computing (topic 44 of 104). It is an intermediate topic. Work through the beginner topics in Software & Computing first.