# ResultsObserver Observes and tracks changes to a collection of persistent models in a model context. ``` final class ResultsObserver where Element : PersistentModel, SectionTitle : Hashable ``` ## Overview `ResultsObserver` automatically monitors changes to models that match specified fetch criteria, providing real-time updates when the underlying data changes. The observer maintains a collection of fetched results, making it ideal for keeping user interfaces synchronized with persistent data. The observer responds to changes from multiple sources: - Local changes made within the same model context - Remote changes from other contexts within the same container - External changes from other processes or CloudKit sync You can configure the observer using either a complete `FetchDescriptor` or individual filter predicates and sort descriptors. The observer is `Observable`, allowing SwiftUI views to automatically update when results change. Use `Never` as the `SectionTitle` type parameter when no sectioning is needed: ```swift let observer = try ResultsObserver( filterBy: #Predicate { $0.isPublished }, sortBy: [SortDescriptor(\.title)], modelContext: context ) ``` Use a concrete type (e.g. `String`) when sectioning by a key path of that type: ```swift let observer = try ResultsObserver( sectionBy: \.genre, modelContext: context ) ``` ## Topics ### Creating a results observer with a fetch descriptor [`init(fetchDescriptor:modelContext:isolation:)`](/documentation/SwiftData/ResultsObserver/init(fetchDescriptor:modelContext:isolation:)) Creates a new unsectioned observer with the given fetch descriptor and model context. [`init(fetchDescriptor:sectionBy:modelContext:isolation:)`](/documentation/SwiftData/ResultsObserver/init(fetchDescriptor:sectionBy:modelContext:isolation:)-7ms14) Creates a new observer with the given fetch descriptor, a String section key path, and a model context. [`init(fetchDescriptor:sectionBy:modelContext:isolation:)`](/documentation/SwiftData/ResultsObserver/init(fetchDescriptor:sectionBy:modelContext:isolation:)-9kg1q) Creates a new observer with the given fetch descriptor, an optional String section key path, and a model context. [`init(fetchDescriptor:modelContainer:isolation:)`](/documentation/SwiftData/ResultsObserver/init(fetchDescriptor:modelContainer:isolation:)) Creates a new unsectioned observer with the given fetch descriptor and model container. [`init(fetchDescriptor:sectionBy:modelContainer:isolation:)`](/documentation/SwiftData/ResultsObserver/init(fetchDescriptor:sectionBy:modelContainer:isolation:)-4tuzk) Creates a new observer with the given fetch descriptor, an optional String section key path, and a model container. [`init(fetchDescriptor:sectionBy:modelContainer:isolation:)`](/documentation/SwiftData/ResultsObserver/init(fetchDescriptor:sectionBy:modelContainer:isolation:)-7wa5c) Creates a new observer with the given fetch descriptor, a String section key path, and a model container. ### Creating a results observer with a predicate [`init(filterBy:sortBy:modelContext:isolation:)`](/documentation/SwiftData/ResultsObserver/init(filterBy:sortBy:modelContext:isolation:)) Creates a new unsectioned observer with individual filter and sort criteria and a model context. [`init(filterBy:sortBy:sectionBy:modelContext:isolation:)`](/documentation/SwiftData/ResultsObserver/init(filterBy:sortBy:sectionBy:modelContext:isolation:)-4ainb) Creates a new observer with individual filter and sort criteria, an optional String section key path, and a model context. [`init(filterBy:sortBy:sectionBy:modelContext:isolation:)`](/documentation/SwiftData/ResultsObserver/init(filterBy:sortBy:sectionBy:modelContext:isolation:)-gsuz) Creates a new observer with individual filter and sort criteria, a String section key path, and a model context. [`init(filterBy:sortBy:modelContainer:isolation:)`](/documentation/SwiftData/ResultsObserver/init(filterBy:sortBy:modelContainer:isolation:)) Creates a new unsectioned observer with individual filter and sort criteria and a model container. [`init(filterBy:sortBy:sectionBy:modelContainer:isolation:)`](/documentation/SwiftData/ResultsObserver/init(filterBy:sortBy:sectionBy:modelContainer:isolation:)-5ufvn) Creates a new observer with individual filter and sort criteria, a String section key path, and a model container. [`init(filterBy:sortBy:sectionBy:modelContainer:isolation:)`](/documentation/SwiftData/ResultsObserver/init(filterBy:sortBy:sectionBy:modelContainer:isolation:)-9lfy0) Creates a new observer with individual filter and sort criteria, an optional String section key path, and a model container. ### Accessing observer properties [`fetchDescriptor`](/documentation/SwiftData/ResultsObserver/fetchDescriptor) The fetch descriptor used to query the model context. [`filterBy`](/documentation/SwiftData/ResultsObserver/filterBy) The predicate used to filter which models are included in the results. [`modelContext`](/documentation/SwiftData/ResultsObserver/modelContext) The model context from which models are fetched. [`sortBy`](/documentation/SwiftData/ResultsObserver/sortBy) The sort descriptors used to order the results. [`sectionBy`](/documentation/SwiftData/ResultsObserver/sectionBy) The key path on the element used to determine section grouping. [`sections`](/documentation/SwiftData/ResultsObserver/sections) The sections computed from the current results, grouped by [`sectionBy`](/documentation/SwiftData/ResultsObserver/sectionBy). ### Accessing observer results [`results`](/documentation/SwiftData/ResultsObserver/results) The current collection of fetched models matching the fetch criteria. [`element(at:)`](/documentation/SwiftData/ResultsObserver/element(at:)) Returns the element at the given index path in the sectioned results. [`indexPath(for:)`](/documentation/SwiftData/ResultsObserver/indexPath(for:)) Returns the index path of the given element within the sectioned results. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)