Angular 2 Updating objects in “real time.”

Question

Hi I’m trying to wrap on how to update a table angular 2.

Here is what I have: Backend: express / MongoDB. Updates are feed into the DB via an external app Data: 90% da

Answer 1

1. Observables are event-based so they can be used to receive events from server leveraging web sockets. Have a look at this article (section "Event-based support"):

   • https://jaxenter.com/reactive-programming-http-and-angular-2-124560.html

2. In fact it's new objects but you can leverage the scan operators to aggregate the content of several events.

   var obs = (...)
   obs.startWith([])
      .scan((acc,value) => acc.concat(value))
      .subscribe((data) => {
        console.log(data);
      });
   

   See this question for more details:

   • Convert a plain string[] into a Observable and concat it to another Observable using RxJS 5

3. If you want to pull with a time interval, you can leverage the interval method:

   Observable.interval(3000).flatMap(() => {
     return this.http.get('/some-request').map(res => res.json());
   }).subscribe((data) => {
     console.log(data);
   });