What is zen-observable?
The zen-observable npm package provides an implementation of the Observable pattern, which is used for managing asynchronous data streams. It allows you to create, transform, and subscribe to data streams in a declarative manner.
What are zen-observable's main functionalities?
Creating an Observable
This feature allows you to create a new Observable instance. The observer object is used to emit values and signal completion. The subscriber receives these values and handles them accordingly.
const { Observable } = require('zen-observable');
const observable = new Observable(observer => {
observer.next('Hello');
observer.next('World');
observer.complete();
});
observable.subscribe({
next(value) { console.log(value); },
complete() { console.log('Done'); }
});
Transforming Observables
This feature allows you to transform the data emitted by an Observable using operators like map. In this example, each value emitted by the original Observable is multiplied by 2.
const { Observable } = require('zen-observable');
const observable = new Observable(observer => {
observer.next(1);
observer.next(2);
observer.next(3);
observer.complete();
});
const transformed = observable.map(x => x * 2);
transformed.subscribe({
next(value) { console.log(value); },
complete() { console.log('Done'); }
});
Combining Observables
This feature allows you to combine multiple Observables into a single Observable. In this example, two Observables are combined and their values are emitted in sequence.
const { Observable } = require('zen-observable');
const observable1 = new Observable(observer => {
observer.next('A');
observer.complete();
});
const observable2 = new Observable(observer => {
observer.next('B');
observer.complete();
});
const combined = Observable.from([observable1, observable2]).flatMap(x => x);
combined.subscribe({
next(value) { console.log(value); },
complete() { console.log('Done'); }
});
Other packages similar to zen-observable
rxjs
RxJS is a library for reactive programming using Observables, to make it easier to compose asynchronous or callback-based code. It is more feature-rich compared to zen-observable and includes a wide range of operators for transforming, combining, and querying Observables.
baconjs
Bacon.js is a functional reactive programming library for JavaScript. It provides a comprehensive set of tools for working with event streams and properties. Compared to zen-observable, Bacon.js offers more advanced features for handling complex data flows.
most
Most.js is a high-performance reactive programming library that focuses on speed and efficiency. It provides a minimalistic API for working with streams. While zen-observable is simpler and easier to use, most.js is optimized for performance and can handle large-scale data streams more efficiently.
zen-observable
An implementation of ES Observables.
Requires ES6 Promises or a Promise polyfill.
Install
npm install zen-observable
Download
Usage
Node:
var Observable = require("zen-observable");
Observable.of(1, 2, 3).forEach(x => console.log(x));
Browser:
<script src="zen-observable.js"></script>
<script>
Observable.of(1, 2, 3).forEach(x => console.log(x));
</script>