Reactive collections

npm install rx-collections

Reactive implementations of ES6 Collections: Set and Map (and Array coming soon) created with TypeScript. Using this library you can pretty easily watch for changes on your collections. RxSet and RxMap classes wrap native equivalents adding changes$ property, which is an RxJS Observable. Data are emitted in the following format:

export interface RxChangeEvent<C, V, K> {
    method: string; // name of invoked method (e.g. "add", "delete")
    key: K;         // string or undefined
    value: V;       // any stored object affected in the operation
    collection: C;  // up-to-date Set or Map instance
}

Example of usage (TypeScript):

import { RxSet } from 'rx-collections';

let set: RxSet<number> = new RxSet<number>();
set.change$.subscribe((event) => {
    console.log('Method', event.method, 'has affected value:', event.value);
    console.log('Current Set state:', event.collection);
    // do something here, e.g. prevent adding null values
    if (event.method === 'add' && event.value === null) {
        event.collection.delete(null);
    }
});
set.add(1).add(2).add(3).add(null).add(4);
// Result: set contains merely 1,2,3,4
console.log('Array created from set:', Array.from(set));

Note: be careful to not accidentally overwrite the object, because observers won't be moved to the new instance. In order to clear it just use built-in .clear() method.

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