---
title: "subscript(_:)"
framework: swiftui
role: symbol
role_heading: Instance Subscript
path: "swiftui/previewcontext/subscript(_:)"
---

# subscript(_:)

Returns the context’s value for a key, or a the key’s default value if the context doesn’t define a value for the key.

## Declaration

```swift
subscript<Key>(key: Key.Type) -> Key.Value where Key : PreviewContextKey { get }
```