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

# predicate

The closure that determines whether publishing should continue.

## Declaration

```swift
let predicate: (Publishers.PrefixWhile<Upstream>.Output) -> Bool
```

## See Also

### Inspecting publisher properties

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