Trait StreamExt

pub trait StreamExt: Stream + Sized {
    // Provided methods
    fn dedup(self) -> Dedup<Self>
       where Self::Item: Clone + PartialEq { ... }
    fn dedup_by_key<T, F>(self, key_fn: F) -> DedupByKey<Self, T, F>
       where T: PartialEq,
             F: FnMut(&Self::Item) -> T { ... }
    fn batch_with<S>(self, batch_done_stream: S) -> BatchWith<Self, S>
       where S: Stream<Item = ()> { ... }
    fn switch(self) -> Switch<Self>
       where Self::Item: Stream { ... }
}

Extensions to the Stream trait.

Provided Methods

fn dedup(self) -> Dedup<Self>

where Self::Item: Clone + PartialEq,

Deduplicate consecutive identical items.

To be able to immediately yield items of the underlying stream once it is produced, but still compare them to the next ones, Dedup keeps a clone of the value that was produced last. If cloning the inner value is expensive but only part of it is used for comparison, you can use dedup_by_key as a more efficient alternative.

fn dedup_by_key<T, F>(self, key_fn: F) -> DedupByKey<Self, T, F>

where T: PartialEq, F: FnMut(&Self::Item) -> T,

Deduplicate consecutive items that the given function produces the same key for.

fn batch_with<S>(self, batch_done_stream: S) -> BatchWith<Self, S>

where S: Stream<Item = ()>,

Buffer the items from self until batch_done_stream produces a value, and return all buffered values in one batch.

batch_done_stream is polled after all ready items from self has been read.

Examples for possible batch_done_streams:

• futures_channel::mpsc::Receiver<()>
• tokio_stream::wrappers::IntervalStream with its item type mapped to () using .map(|_| ()) (use tokio_stream::StreamExt for map)

fn switch(self) -> Switch<Self>

where Self::Item: Stream,

Flattens a stream of streams by always keeping one inner stream and yielding its items until the outer stream produces a new inner stream, at which point the inner stream to yield items from is switched to the new one.

Equivalent to RxJS’es switchAll.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<S: Stream> StreamExt for S