---
title: transform
framework: combine
role: symbol
role_heading: Instance Property
path: combine/publishers/flatmap/transform
---

# transform

A closure that takes an element as a parameter and returns a publisher that produces elements of that type.

## Declaration

```swift
let transform: (Upstream.Output) -> NewPublisher
```

## See Also

### Inspecting publisher properties

- [upstream](combine/publishers/flatmap/upstream.md)
- [maxPublishers](combine/publishers/flatmap/maxpublishers.md)