Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/staltz/toy-rx
A tiny implementation of RxJS that actually works, for learning
https://github.com/staltz/toy-rx
observables reactive reactive-programming rx rxjs rxjs5
Last synced: 21 days ago
JSON representation
A tiny implementation of RxJS that actually works, for learning
- Host: GitHub
- URL: https://github.com/staltz/toy-rx
- Owner: staltz
- License: mit
- Created: 2017-03-25T11:59:21.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2017-03-25T12:09:42.000Z (almost 8 years ago)
- Last Synced: 2025-01-03T01:17:12.735Z (29 days ago)
- Topics: observables, reactive, reactive-programming, rx, rxjs, rxjs5
- Language: JavaScript
- Size: 9.77 KB
- Stars: 295
- Watchers: 10
- Forks: 29
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-reactive-programming - Toy RxJS
README
# Toy RxJS
A tiny implementation of RxJS that actually works, for learning.
## Usage
`npm install toy-rx`
```js
const Rx = require('toy-rx')
Rx.Observable.fromEvent = require('toy-rx/fromEvent')
Rx.Observable.prototype.map = require('toy-rx/map')
Rx.Observable.prototype.filter = require('toy-rx/filter')
Rx.Observable.prototype.delay = require('toy-rx/delay')
Rx.Observable.fromEvent(document, 'click')
.delay(500)
.map(ev => ev.clientX)
.filter(x => x < 200)
.subscribe({
next: x => console.log(x),
error: e => console.error(e),
complete: () => {},
})
```
## Why
I made this so people can look into the implementation of a simple RxJS and feel like they can actually understand it. I mean, the implementation is literally this below:
```js
class Subscription {
constructor(unsubscribe) {
this.unsubscribe = unsubscribe;
}
}
class Subscriber extends Subscription {
constructor(observer) {
super(function unsubscribe() {});
this.observer = observer;
}
next(x) {
this.observer.next(x);
}
error(e) {
this.observer.error(e);
this.unsubscribe();
}
complete() {
this.observer.complete();
this.unsubscribe();
}
}
class Observable {
constructor(subscribe) {
this.subscribe = subscribe;
}
static create(subscribe) {
return new Observable(function internalSubscribe(observer) {
const subscriber = new Subscriber(observer);
const subscription = subscribe(subscriber);
subscriber.unsubscribe = subscription.unsubscribe.bind(subscription);
return subscription;
});
}
}
class Subject extends Observable {
constructor() {
super(function subscribe(observer) {
this.observers.push(observer);
return new Subscription(() => {
const index = this.observers.indexOf(observer);
if (index >= 0) this.observers.splice(index, 1);
});
});
this.observers = [];
}
next(x) {
this.observers.forEach((observer) => observer.next(x));
}
error(e) {
this.observers.forEach((observer) => observer.error(e));
}
complete() {
this.observers.forEach((observer) => observer.complete());
}
}
```
See? It fit easily in a README and you weren't scared of looking at it even though it's source code. That was `index.js`.
Where are all the operators? Well, here's `map` for instance:
```js
function map(transformFn) {
const inObservable = this;
const outObservable = Rx.Observable.create(function subscribe(outObserver) {
const inObserver = {
next: (x) => {
try {
var y = transformFn(x);
} catch (e) {
outObserver.error(e);
return;
}
outObserver.next(y);
},
error: (e) => {
outObserver.error(e);
},
complete: () => {
outObserver.complete();
}
};
return inObservable.subscribe(inObserver);
});
return outObservable;
}
```
What about `filter`, and `combineLatest` and all the rest? Just look for yourself, don't be afraid to click on the JS files in this project.
## How is this different to the official RxJS?
This is just meant for education. It's missing a ton of stuff that the [official RxJS](http://reactivex.io/rxjs/) covers, such as:
- Subscribe supports partial Observer objects
- Subscribe supports functions as arguments
- Dozens of useful operators
- The wonderful and underrated [Lift Architecture](https://github.com/ReactiveX/rxjs/blob/3ced24f2192289e441e88368c02c9df86bcb11e0/src/Observable.ts#L60-L72)
- Schedulers (and in turn, testing with marble diagrams)
- Corner cases covered against bugs
- Thorough documentation and examples
- Thorough tests
- TypeScript support
Overall, this project is a simplification of RxJS which describes "close enough" how RxJS works, but has a lot of holes and bugs because we deliberately are not taking care of many corner cases in this code.
Use this project to gain confidence peeking into the implementation of a library and get familiar with RxJS internals.
## Contributing
Don't bother submitting PRs for this project to add more operators and more bug safety. Let's just keep this simple enough to read for any developer with a few minutes of free time.