Pros of proposal-observable

• Simpler and more lightweight, focusing on core Observable functionality
• Designed as a potential ECMAScript standard, aiming for broader adoption
• Provides a foundational API that can be extended by libraries like RxJS

Cons of proposal-observable

• Limited feature set compared to RxJS's extensive operators and utilities
• Less mature ecosystem and community support
• Lacks advanced functionality for complex reactive programming scenarios

Code Comparison

proposal-observable:

const observable = new Observable(observer => {
  observer.next(1);
  observer.next(2);
  observer.complete();
});
observable.subscribe(console.log);

RxJS:

import { Observable } from 'rxjs';

const observable = new Observable(subscriber => {
  subscriber.next(1);
  subscriber.next(2);
  subscriber.complete();
});
observable.subscribe(console.log);

The basic usage is similar, but RxJS offers a wide range of operators and utilities for more complex operations:

import { of } from 'rxjs';
import { map, filter } from 'rxjs/operators';

of(1, 2, 3, 4, 5)
  .pipe(
    filter(n => n % 2 === 0),
    map(n => n * 2)
  )
  .subscribe(console.log);

proposal-observable focuses on providing a standardized Observable implementation, while RxJS offers a comprehensive toolkit for reactive programming with numerous operators and utilities.

Pros of MobX

• Simpler learning curve and less boilerplate code
• Automatic tracking of observables and reactions
• Better performance for complex state management scenarios

Cons of MobX

• Less control over data flow and side effects
• Smaller ecosystem and community compared to RxJS
• Potential for overuse of mutable state

Code Comparison

MobX:

import { observable, action } from 'mobx';

class Store {
  @observable count = 0;
  @action increment() {
    this.count++;
  }
}

RxJS:

import { BehaviorSubject } from 'rxjs';

const count$ = new BehaviorSubject(0);
const increment = () => {
  count$.next(count$.getValue() + 1);
};

Summary

MobX and RxJS are both popular libraries for managing state and handling asynchronous operations in JavaScript applications. MobX focuses on simplicity and ease of use, with automatic tracking of observables and reactions. It's well-suited for complex state management scenarios and offers better performance in such cases. However, it provides less control over data flow and has a smaller ecosystem compared to RxJS.

RxJS, on the other hand, offers a more powerful and flexible approach to reactive programming, with a larger ecosystem and community support. It provides fine-grained control over data streams and side effects but comes with a steeper learning curve and more boilerplate code.

The choice between MobX and RxJS depends on the specific requirements of your project, team expertise, and preferred programming paradigms.

Pros of RxJava

• Better performance and efficiency in Java environments
• More mature and stable, with a longer history in the Java ecosystem
• Extensive support for Android development

Cons of RxJava

• Steeper learning curve for developers new to reactive programming
• Less seamless integration with web technologies compared to RxJS

Code Comparison

RxJava:

Observable.just("Hello", "World")
    .map(String::toUpperCase)
    .subscribe(System.out::println);

RxJS:

import { of } from 'rxjs';
import { map } from 'rxjs/operators';

of("Hello", "World")
  .pipe(map(x => x.toUpperCase()))
  .subscribe(console.log);

Both libraries share similar concepts and operators, but RxJava is tailored for Java and Android development, while RxJS is designed for JavaScript environments, particularly web applications. RxJava offers better performance in Java-based systems, while RxJS provides smoother integration with web technologies and frameworks like Angular. The choice between the two depends on the target platform and development ecosystem.

Pros of RxSwift

• Native iOS development support with Swift-specific optimizations
• Seamless integration with Apple's ecosystem and frameworks
• Strong type safety and compile-time checks inherent to Swift

Cons of RxSwift

• Limited to iOS and macOS platforms
• Smaller community and ecosystem compared to RxJS
• Steeper learning curve for developers new to functional reactive programming

Code Comparison

RxSwift:

Observable.from([1, 2, 3, 4, 5])
    .filter { $0 % 2 == 0 }
    .map { $0 * 2 }
    .subscribe(onNext: { print($0) })

RxJS:

from([1, 2, 3, 4, 5])
    .pipe(
        filter(x => x % 2 === 0),
        map(x => x * 2)
    )
    .subscribe(x => console.log(x));

Both RxSwift and RxJS implement the ReactiveX pattern, providing similar functionality for handling asynchronous data streams. RxSwift is tailored for Swift and iOS development, offering tight integration with Apple's ecosystem and leveraging Swift's type safety. RxJS, on the other hand, is more versatile and can be used across various JavaScript environments, including browsers and Node.js.

While RxSwift excels in native iOS development, RxJS benefits from a larger community, more extensive documentation, and broader platform support. The choice between the two largely depends on the target platform and the developer's familiarity with the respective programming languages.

Pros of redux-observable

• Specifically designed for Redux, providing seamless integration with Redux applications
• Offers middleware for handling side effects in Redux, simplifying complex async operations
• Leverages the power of RxJS while providing a more focused API for Redux use cases

Cons of redux-observable

• Steeper learning curve for developers not familiar with RxJS concepts
• More opinionated and less flexible compared to RxJS for general-purpose reactive programming
• Smaller community and ecosystem compared to RxJS

Code Comparison

redux-observable:

const pingEpic = action$ => action$.pipe(
  ofType('PING'),
  delay(1000),
  mapTo({ type: 'PONG' })
);

RxJS:

const ping$ = new Subject();
const pong$ = ping$.pipe(
  delay(1000),
  map(() => 'PONG')
);

Summary

redux-observable is a specialized library built on top of RxJS, tailored for Redux applications. It provides a more focused API for handling side effects in Redux, making it easier to manage complex asynchronous operations. However, it comes with a steeper learning curve and is less flexible for general-purpose reactive programming compared to RxJS.

RxJS, on the other hand, is a more versatile and widely-used reactive programming library. It offers a broader range of operators and can be used in various contexts beyond Redux applications. RxJS has a larger community and ecosystem, but may require more setup and configuration when used with Redux.

Pros of Cycle.js

• Provides a complete framework for building reactive applications
• Emphasizes functional and reactive programming paradigms
• Offers a unique "dialogue" abstraction for handling side effects

Cons of Cycle.js

• Steeper learning curve due to its unique architecture
• Smaller community and ecosystem compared to RxJS
• Less flexibility for integration with other libraries or frameworks

Code Comparison

Cycle.js:

function main(sources) {
  const input$ = sources.DOM.select('.field').events('input');
  const name$ = input$.map(ev => ev.target.value).startWith('');
  const vdom$ = name$.map(name =>
    div([
      label('Name:'),
      input('.field', {attrs: {type: 'text'}}),
      h1(`Hello ${name}`)
    ])
  );
  return { DOM: vdom$ };
}

RxJS:

const input$ = fromEvent(inputElement, 'input');
const name$ = input$.pipe(
  map(event => event.target.value),
  startWith('')
);
name$.subscribe(name => {
  outputElement.textContent = `Hello ${name}`;
});

Both examples demonstrate reactive programming, but Cycle.js provides a more structured approach with its framework, while RxJS offers more flexibility as a standalone library for reactive programming.