RxSwift Traits

• Traits are observables with a narrow set of behaviors.
• Traits are simply a wrapper struct with a single read-only Observable sequence property.

Why Traits?

1. Help communicate and ensure sequence properties.
2. They are specialized in what you want to do. (Target more specific use-cases)
3. Highly Expressive
4. Communicates developer’s intention
5. Provide syntactical sugar.

Note: Traits are entirely optional. You are free to use raw observables but I don’t find any reason to not use it.

Three Types of RxSwift Traits

Single

• Emits exactly one element, or an error. (Success or Error)
• While using Single you need to make sure one thing that it emits only a single element. It could result in the following error: Sequence contains more than one element.
• Common Usages -DB Fetch Operations, Network Requests

Output for above code -
Value is ["designation": "iOS Developer", "name": "John Doe"]
Disposed trait resources

Completable

• Emits an event case is “.completed” or “.error”
• Emits zero elements. (No data)
• Completable is used where we don’t care about the element result (data) but care about the fact that operation is completed.
• Common Usage -Updating a Cache.

Output for above code -
Completed Event
Disposed trait resources

Maybe

• Emits an event case is “.success” or “.completed” or “.error”
• Emits an element.
• Maybe can be used in the use-case where it doesn’t necessarily have to emit an element.
• It can either emit a single element, complete without emitting an element or emit an error.
• Common Usage -Fetching Data from Cache.

Output for above code -
Value is Number is greater than 5
Disposed trait resources

Thank you. I hope this helps!