most-subject

Subjects for @most/core

Get it

yarn add most-subject
# or
npm install --save most-subject

API Documentation

create<A>(): Subject<A, A>

create<A, B>(f: (stream: Stream<A>) => Stream<B>): Subject<A, B>

Returns an tuple containing a AttachSink and a Stream. AttachSink can be used to imperatively control the events flowing through the Stream or declaratively using attach. Optionally, a function can be applied to the Stream, and the return value of that function will be returned as the second tuple value.

import { create, event } from 'most-subject'
import { runEffects, propagateEventTask } from '@most/core'
import { newDefaultScheduler, currentTime } from '@most/scheduler'

// Create a new `Scheduler` for use in our application.
// Usually, you will want to only have one Scheduler, and it should be shared 
// across your application
const scheduler = newDefaultScheduler()

// Create our sink and our stream.
// NOTE: stream is the resulting value of tap(console.log, stream).
const [ sink, stream ] = create(tap<number>(console.log))

// Pushes events into our stream.
const next = (n: number) => event(currentTime(scheduler), n, sink)

// Activate our stream.
runEffects(stream, scheduler)

// Simulate asynchronous data fetching,
// and then push values into our stream.
Promise.resolve([ 1, 2, 3 ])
 .then(data => data.forEach(next))

attach<A>(attachSink: AttachSink<A>, stream: Stream<A>): Stream<A>

Create circular dependencies with additional logic to help avoid memory leaks.

WARNING: There isn't any logic for breaking infinite loops.

import { Stream } from '@most/types'
import { create, attach } from 'most-subject'
import { periodic, scan, take, runEffects } from '@most/core'
import { newDefaultScheduler } from '@most/scheduler'

// Create a new Scheduler for use in our application.
// Usually, you will want to only have one Scheduler, and it should be shared 
// across your application.
const scheduler = newDefaultScheduler()

const [ sink, stream ] = create<number>()

// Listen to our stream.
// It will log 1, 2, and 3.
runEffects(tap(console.log, take(3, stream)), scheduler)

const origin = scan(x => x + 1, 0, periodic(100))

attach(origin)

event<A>(time: Time, value: A, sink: Sink<A>): void

A curried function for calling Sink.event(time, value).

error(time: Time, error: Error, sink: Sink<any>): void

A curried function for calling Sink.error(time, error).

end(time: Time, sink: Sink<any>): void

A curried function for calling Sink.end(time).

Subject<A, B>

import { Sink, Stream } from '@most/types'

export type Subject<A, B> = [AttachSink<A>, Stream<B>]

AttachSink<A>

import { Sink } from '@most/types'

export AttachSink<A> extends Sink<A> {
  attach(stream: Stream<A>): Stream<A>
}