Class ExpandOperator

Namespace

RxSharp.Operators

Assembly

RxSharp.dll

Extension methods implementing the expand operator.

public static class ExpandOperator

Inheritance

System.Object

ExpandOperator

Remarks

Like MergeMapOperator, this port always merges with unbounded concurrency: there is no concurrent limit parameter, since Puppeteer's own usage (the motivating consumer of this port) never needs to cap in-flight inner subscriptions. Unlike MergeMap, an unbounded concurrency limit is arguably more important to flag here: a project that never returns an empty/completing-without-emitting observable recurses forever, and — since C# gives no bottom type — project's return type must be Observable<T> (the same as the source), so it is easy to write an accidentally-infinite expansion. Rely on a downstream operator like Take to cut it off, exactly as rxjs's own documentation examples do.

Methods

Expand<T>(Observable<T>, Func<T, Observable<T>>)

Recursively projects each value — from source itself, and then from every inner observable project produces — back through project, merging every resulting inner observable into the output.

public static Observable<T> Expand<T>(this Observable<T> source, Func<T, Observable<T>> project)

Parameters

source Observable<T>

The source sequence.

project Func<T, Observable<T>>

A function that maps each value (from the source or from a previous expansion) to an inner observable to expand further.

Returns

Observable<T>

An observable that emits every value encountered while recursively expanding source.

Type Parameters

T

The type of values emitted by source, by every inner observable, and by the output.

Remarks

See the indexed overload for the full behavior description.

Expand<T>(Observable<T>, Func<T, int, Observable<T>>)

Recursively projects each value — from source itself, and then from every inner observable project produces — along with its zero-based expansion index, back through project, merging every resulting inner observable into the output.

public static Observable<T> Expand<T>(this Observable<T> source, Func<T, int, Observable<T>> project)

Parameters

source Observable<T>

The source sequence.

project Func<T, int, Observable<T>>

A function that maps each value and its expansion index (starting at 0) to an inner observable to expand further.

Returns

Observable<T>

An observable that emits every value encountered while recursively expanding source.

Type Parameters

T

The type of values emitted by source, by every inner observable, and by the output.

Remarks

Every value seen — whether it came directly from source or from a previously projected inner observable — is immediately forwarded to the output, and is also passed to project to produce a further inner observable to merge in (which is itself expanded the same way, recursively). The output completes once source has completed and every inner observable produced, directly or recursively, has also completed. If project throws, or any inner observable errors, the exception is forwarded to the subscriber via OnError instead of propagating synchronously.