scratch.tsx

import { Observable } from '../../../../projects/demo-portal-angular/src/main/storefront-spa-webapp/node_modules/rxjs/Observable';

class CacheApi {
    private cachedStream: Observable;
    protected cached: boolean = false;

    public setCache(stream: Observable<any>) {
        this.cachedStream = stream.share();
        this.cached = true;
    }

    public getCache(): Observable<any> {
        return this.cachedStream;
    }

    public get cached(): boolean {
        return this.cached;
    }
}

const cacheMap = new WeakMap();
export function cache(TTL = 1000 * 60 * 10): Function {
    return function (target: any, propertyKey: any, descriptor: any) {
        setTimeout(() => {
            cacheMap.delete(property);
        }, TTL);
        return _.memoize(target[property]);
    }
}

class Api {

    @cache()
    fetchOrders(): Observable<number> {
        return Observable.of(1);
    }
}

class Api2 extends CacheApi {

    constructor() {
        super(this);
    }

    fetchOrders(): Observable<number> {
        if (!this.cached) {
            let stream = Observable.of(1);
            this.setCache(stream);
        }

        return this.getCache();
    }
}