---
title: keyPath0
framework: combine
role: symbol
role_heading: Instance Property
path: combine/publishers/mapkeypath3/keypath0
---

# keyPath0

The key path of a property to publish.

## Declaration

```swift
let keyPath0: KeyPath<Upstream.Output, Output0>
```

## See Also

### Inspecting publisher properties

- [upstream](combine/publishers/mapkeypath3/upstream.md)
- [keyPath1](combine/publishers/mapkeypath3/keypath1.md)
- [keyPath2](combine/publishers/mapkeypath3/keypath2.md)