Question 1

How to wrap URLSession with Promise in Swift?

Accepted Answer

Use the Promise initializer with a work block that calls fulfill or reject based on URLSession's completion handler. The README shows an example handling data, response, and error to convert completion-block APIs into promises.

Question 2

Promise vs Combine in Swift: which should I use?

Accepted Answer

Promise is simpler and focused on single-value async operations with chainable APIs, ideal for tasks like network requests. Combine is Apple's reactive framework for event streams; choose Promise for straightforward async chains, Combine for complex publishers and subscribers.

Question 3

How to handle errors in Khanlou's Promise library?

Accepted Answer

Add a catch block at the end of the promise chain to centralize error handling; thrown errors in then blocks are automatically converted to rejections, preventing further execution and simplifying error management as demonstrated in the examples.

Question 4

Can I use Promise with Swift's async/await?

Accepted Answer

This library predates async/await, so while you can bridge them with adapters, it's not native. For new projects, consider Swift's built-in async/await for better integration, but Promise offers a familiar pattern for legacy or specific use cases.

Question 5

How to run multiple promises concurrently with Promise?

Accepted Answer

Use Promises.all to wait for all promises to fulfill, returning an array of values. The README demonstrates this by mapping over an array and using all to handle simultaneous operations like following multiple users.

Question 6

What is InvalidatableQueue and how do I use it in UITableView cells?

Accepted Answer

InvalidatableQueue is an execution context that can be invalidated to discard blocks; use it in table cells by assigning it in showImage methods and invalidating on prepareForReuse to prevent stale updates, as shown in the README example.

Promise

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