---
title: prefix
framework: combine
role: symbol
role_heading: Instance Property
path: combine/publishers/assertnofailure/prefix
---

# prefix

The string used at the beginning of the fatal error message.

## Declaration

```swift
let prefix: String
```

## See Also

### Inspecting publisher properties

- [upstream](combine/publishers/assertnofailure/upstream.md)
- [file](combine/publishers/assertnofailure/file.md)
- [line](combine/publishers/assertnofailure/line.md)