---
title: predicate
framework: combine
role: symbol
role_heading: Instance Property
path: combine/publishers/trycontainswhere/predicate
---

# predicate

The error-throwing closure that determines whether this publisher should emit a Boolean true element.

## Declaration

```swift
let predicate: (Upstream.Output) throws -> Bool
```

## See Also

### Inspecting publisher properties

- [upstream](combine/publishers/trycontainswhere/upstream.md)