SafeFetching
This library offers a DSL (Domain Specific Language) to safely build predicates and requests to fetch a CoreData store. Also a wrapper around NSFetchedResultsController is offered to publish arrays of NSManagedObject to be used with a NSDiffableDataSource.
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Note This repository is a split of CoreDataCandy to offer the fetching features alone
Convenient and safe fetching
For any CoreData entity generated by Xcode, the only required step is to make it implement Fetchable.
final class RandomEntity: NSManagedObject {
@NSManaged var score = 0.0
@NSManaged var name: String? = ""
}
extension RandomEntity: Fetchable {}
Then it's possible to use the DSL to build a request. The last step can either get the built request as NSFetchRequest
or execute the request in the provided context.
RandomEntity.request()
.all(after: 10)
.where(\.score >= 15 || \.name != "Joe")
.sorted(by: .ascending(\.score), .descending(\.name))
.setting(\.returnsDistinctResults, to: true)
.nsValue
RandomEntity.request()
.all(after: 10)
.where(\.score >= 15 || \.name != "Joe")
.sorted(by: .ascending(\.score), .descending(\.name))
.setting(\.returnsDistinctResults, to: true)
.fetch(in: context) // returns [RandomEntity]
Fetch update
When the entity type implements Fetchable, it's possible to call the static updatePublisher function to create a publisher backed by a NSFetchedResultsController that will emit arrays of the entity. This is especially useful when working with a NSDiffableDataSource.
let request = RandomEntity.request()
.all(after: 10)
.where(\.score >= 15 || \.name != "Joe")
.sorted(by: .ascending(\.score), .descending(\.name))
.nsValue
RandomEntity.updatePublisher(
sortingBy: .ascending(\.name),
for: request,
in: context
) // emits [StubEntity]
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