<!--
{
  "availability" : [
    "iOS: 11.3.0 -",
    "iPadOS: 11.3.0 -",
    "macCatalyst: 11.3.0 -",
    "macOS: 11.0.0 -",
    "visionOS: 1.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "ClassKit",
  "identifier" : "/documentation/ClassKit/CLSDataStore/contexts(matching:completion:)",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Method",
  "symbol" : {
    "kind" : "Instance Method",
    "modules" : [
      "ClassKit"
    ],
    "preciseIdentifier" : "c:objc(cs)CLSDataStore(im)contextsMatchingPredicate:completion:"
  },
  "title" : "contexts(matching:completion:)"
}
-->

# contexts(matching:completion:)

Fetches all the contexts matching a predicate.

```
func contexts(matching predicate: NSPredicate, completion: @escaping @Sendable ([CLSContext], (any Error)?) -> Void)
```

## Parameters

`predicate`

A predicate that the method uses to search for contexts.

`completion`

A closure that the method calls with the array of contexts that match the predicate and an optional error that indicates the reason for failure, if any.

## Discussion

> Important:
> You can call this method from synchronous code using a completion handler, as shown on this page, or you can call it as an asynchronous method that has the following declaration:
> 
> ```swift
> func contexts(matching predicate: NSPredicate) async throws -> [CLSContext]
> ```
> 
> For information about concurrency and asynchronous code in Swift, see <doc://com.apple.documentation/documentation/Swift/calling-objective-c-apis-asynchronously>.

Use the predicate keys defined in [`CLSPredicateKeyPath`](/documentation/ClassKit/CLSPredicateKeyPath) to create a predicate that you pass to this method to search for contexts matching certain criteria.

For example, to print the titles of all the children of the main app context:

```swift
let store = CLSDataStore.shared
let predicate = NSPredicate(format: "%K = %@", CLSPredicateKeyPath.parent as CVarArg,
                                               store.mainAppContext)
store.contexts(matching: predicate) { contexts, _ in
    for context in contexts {
        print(context.title)
    }
}
```

> Important:
> ClassKit calls your completion handler on an arbitrary thread. If you need to do work on a particular thread from inside the handler, dispatch that work to the appropriate queue.

---

Copyright &copy; 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)