What are the main differences between RxSwift Signal and Driver in terms of their purpose and behavior?

In RxSwift, Signal and Driver are special types of streams that differ in behavior and purpose:

• Signal:

  • Does not contain an initial value (does not cache the last one).
  • Cannot error out (does not emit errors).
  • Subscribers receive events only after subscribing.
  • Used for UI events that do not require an initial state.

• Driver:

  • Always contains an initial value (caches the last one).
  • Cannot error out.
  • Subscribers immediately receive the last value upon subscribing.
  • Guarantees execution on the main thread.
  • Used for binding data to UI where having the current state and thread safety are important.

In summary, Driver is a more "safe" and convenient stream for UI with caching and main thread guarantee, while Signal is for events where an initial value is not needed and simplicity is important.