# Struct actix_web::actix::actix::fut::StreamMap[−]

    #[must_use = "streams do nothing unless polled"]
    pub struct StreamMap<S, F> { /* fields omitted */ }

A stream combinator which will change the type of a stream from one type to another.

This is produced by the `ActorStream::map` method.

## Trait Implementations

###

`impl<S, F, U> ActorStream for StreamMap<S, F> where F: FnMut(<S as ActorStream>::Item, &mut <S as ActorStream>::Actor, &mut <<S as ActorStream>::Actor as Actor>::Context) -> U, S: ActorStream,`

#### `type Item = U`

The type of item this stream will yield on success.

#### `type Error = <S as ActorStream>::Error`

The type of error this stream may generate.

#### `type Actor = <S as ActorStream>::Actor`

The actor within which this stream runs.

####

`fn poll( &mut self, act: &mut <StreamMap<S, F> as ActorStream>::Actor, ctx: &mut <<S as ActorStream>::Actor as Actor>::Context ) -> Result<Async<Option<U>>, <S as ActorStream>::Error>` |

####

`fn map<U, F>(self, f: F) -> StreamMap<Self, F> where F: FnMut(Self::Item, &mut Self::Actor, &mut <Self::Actor as Actor>::Context) -> U,` |

Converts a stream of type `T` to a stream of type `U`.

####

`fn map_err<E, F>(self, f: F) -> StreamMapErr<Self, F> where F: FnMut(Self::Error, &mut Self::Actor, &mut <Self::Actor as Actor>::Context) -> E,` |

Converts a stream of error type `T` to a stream of error type `E`.

####

`fn then<F, U>(self, f: F) -> StreamThen<Self, F, U> where F: FnMut(Result<Self::Item, Self::Error>, &mut Self::Actor, &mut <Self::Actor as Actor>::Context) -> U, U: IntoActorFuture<Actor = Self::Actor>,` |

Chain on a computation for when a value is ready, passing the resulting item to the provided closure `f`. Read more

####

`fn and_then<F, U>(self, f: F) -> StreamAndThen<Self, F, U> where F: FnMut(Self::Item, &mut Self::Actor, &mut <Self::Actor as Actor>::Context) -> U, U: IntoActorFuture<Error = Self::Error, Actor = Self::Actor>,` |

Chain on a computation for when a value is ready, passing the successful results to the provided closure `f`. Read more

####

`fn fold<F, T, Fut>(self, init: T, f: F) -> StreamFold<Self, F, Fut, T> where F: FnMut(T, Self::Item, &mut Self::Actor, &mut <Self::Actor as Actor>::Context) -> Fut, Fut: IntoActorFuture<Actor = Self::Actor, Item = T>, Self::Error: From<<Fut as IntoActorFuture>::Error>,` |

Execute an accumulating computation over a stream, collecting all the values into one final result. Read more

####

`fn timeout(self, timeout: Duration, err: Self::Error) -> StreamTimeout<Self> where Self::Error: Clone,` |

Add timeout to stream. Read more

####

`fn finish(self) -> StreamFinish<Self>` |

Converts a stream to a future that resolves when stream finishes.

###

`impl<S, F> Debug for StreamMap<S, F> where F: Debug, S: Debug,`

####

`fn fmt(&self, f: &mut Formatter) -> Result<(), Error>` |

Formats the value using the given formatter. Read more

## Auto Trait Implementations

###

`impl<S, F> Send for StreamMap<S, F> where F: Send, S: Send,`

###

`impl<S, F> Sync for StreamMap<S, F> where F: Sync, S: Sync,`

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