launch.io/dist/esm/utils/Observable.js

Launch.IO is an Ultra Hip, Simple, and Fast, Time Traveling React State Management Library

export default class Observable {
    constructor(value) {
        this.value = value;
        this.listeners = new Set();
    }
    _update(value) {
        this.value = value;
        this.emit();
    }
    emit() {
        for (const listener of this.listeners) {
            listener(this.snapshot());
        }
    }
    update(value) {
        this._update(value);
    }
    snapshot() {
        return this.value;
    }
    subscribe(callback) {
        this.listeners.add(callback);
        return {
            disconnect: () => {
                this.listeners.delete(callback);
            },
        };
    }
}