Motivation

This library is based on the brilliant Callbag spec by André Staltz, which allows creating both pullable and listenable streams from simple functions. That makes it lightweight and flexible and that's why it shines when used as a primitive for libraries or apps!

Get started

Install

npm install --save reactive-fns
# or
yarn add reactive-fns

Use

import { pipe, interval, tap, map, filter, forEach } from 'reactive-fns'

pipe(
    interval(1000),
    tap(v => console.log('Before: ' + v)),
    map(x => x * 3),
    filter(x => x % 2 === 0),
    forEach(v => console.log('After: ' + v))
)

Source Creators

• fromEvent: Listen to DOM event.
• fromIter: Convert an Iterable or Iterator to a pullable stream (only send data when requested).
• fromPromise: Converts a promise to a stream.
• interval: Emits an increasing number at given intervals.
• of: Convert static value(s) to a stream.

Operators

• debounce: Debounces incoming values.
• filter: Filters incoming values.
• flatten: Flattens higher-order streams.
• map: Transforms incoming values.
• mapTo: Transforms the contents of the stream to the provided value.
• sample: Operator that samples a pullable stream when a listenable stream emits.
• scan: Combine consecutive values from stream.
• share: Multicast stream.
• skip: Ignores the first n of the stream.
• skipRepeats: Skips consecutive values that pass the given predicate (defaults to a === b).
• startWith: Start with given values.
• take: Take a maximum number of values from stream.
• withPrevious: Puts the previous value with current in an array.

Combinators

• concat: Combine streams by putting one stream after the previous stream ends.
• merge: Merges given streams, emitting when each one emits.
• combine: Combines given streams, emits arrays of latest values of each.

Utilities

• extract: Get the last emitted value if it exists.
• forEach: Subscribes to given stream.
• pipe: Pipes streams to operators to sinks.
• tap: Taps into given stream.

Learn more

• Callbag basics
• Why we need callbags