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# Publishers.DropUntilOutput

A publisher that ignores elements from the upstream publisher until it receives an element from second publisher.

```
struct DropUntilOutput<Upstream, Other> where Upstream : Publisher, Other : Publisher, Upstream.Failure == Other.Failure
```

## Topics

### Creating a drop until output publisher

[`init(upstream:other:)`](/documentation/Combine/Publishers/DropUntilOutput/init(upstream:other:))

Creates a publisher that ignores elements from the upstream publisher until it receives an element from another publisher.

### Declaring supporting types

[`Publishers.DropUntilOutput.Output`](/documentation/Combine/Publishers/DropUntilOutput/Output)

The kind of values published by this publisher.

[`Publishers.DropUntilOutput.Failure`](/documentation/Combine/Publishers/DropUntilOutput/Failure)

The kind of errors this publisher might publish.

### Inspecting publisher properties

[`upstream`](/documentation/Combine/Publishers/DropUntilOutput/upstream)

The publisher from which this publisher receives its elements.

[`other`](/documentation/Combine/Publishers/DropUntilOutput/other)

A publisher to monitor for its first emitted element.

### Comparing publishers

[`==(_:_:)`](/documentation/Combine/Publishers/DropUntilOutput/==(_:_:))

Returns a Boolean value that indicates whether two publishers are equivalent.


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