export class Reactive { listeners: any; contents: any; constructor(obj: Record) { this.contents = obj; this.listeners = {}; this.makeReactive(obj); } makeReactive(obj: Record) { Object.keys(obj).forEach(prop => this.makePropReactive(obj, prop)); } makePropReactive(obj: Record, key: string) { let value = obj[key]; // Gotta be careful with this here // eslint-disable-next-line @typescript-eslint/no-this-alias const that = this; Object.defineProperty(obj, key, { get() { return value; }, set(newValue) { value = newValue; that.notify(key); } }); } listen(prop: string, handler: any) { if (!this.listeners[prop]) this.listeners[prop] = []; this.listeners[prop].push(handler); } notify(prop: string) { if (!this.listeners[prop]) return; this.listeners[prop].forEach((listener: any) => listener(this.contents[prop])); } }