symbol-observable
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Package description
The symbol-observable package is primarily used to polyfill the Observable symbol, which is a proposed addition to the ECMAScript standard. It allows JavaScript objects to be observable, meaning that other objects can subscribe to them and react to changes. This is particularly useful in reactive programming models and libraries, such as RxJS, where data streams and their transformations are a core concept.
Polyfill for Observable Symbol
This code demonstrates how to use the symbol-observable package to make an object observable. It defines a simple observable that emits 'hi' every second. An observer subscribes to this observable to log the emitted values. This showcases how symbol-observable can be used to implement the observer pattern in JavaScript.
"use strict";
const symbolObservable = require('symbol-observable').default;
console.log(typeof symbolObservable); // 'symbol' in environments with native Symbol support
const obj = {};
obj[symbolObservable] = function () {
return {
subscribe(observer) {
const intervalID = setInterval(() => observer.next('hi'), 1000);
return {
unsubscribe() {
clearInterval(intervalID);
}
};
}
};
};
const observable = obj[symbolObservable]();
const subscription = observable.subscribe({
next(val) { console.log(val); },
complete() { console.log('Done'); }
});
// Later:
// subscription.unsubscribe();RxJS is a library for reactive programming using Observables, to make it easier to compose asynchronous or callback-based code. Unlike symbol-observable, which provides the basic polyfill for the Observable symbol, RxJS offers a comprehensive suite of operators for transforming, combining, and managing asynchronous streams of data.
Zen Observable is a lightweight implementation of Observables for JavaScript. It provides an Observable class that can be used directly, without needing a polyfill. Compared to symbol-observable, Zen Observable offers more out-of-the-box functionality, including a full implementation of the Observable spec, rather than just providing the symbol.
Changelog
Readme
Symbol.observable ponyfill
$ npm install --save symbol-observable
const symbolObservable = require('symbol-observable');
console.log(symbolObservable);
//=> Symbol(observable)
MIT © Sindre Sorhus
FAQs
Symbol.observable ponyfill
We found that symbol-observable demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 3 open source maintainers collaborating on the project.
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