Angular2-Meteor zone() method


#1

In the angular2-meteor tutorial step3, we use a zone method. Code:

import { Component } from ‘@angular/core’;
import { Observable } from ‘rxjs/Observable’;

import { Parties } from ‘…/…/both/collections/parties.collection’;

…some lines skipped…
template
})
export class AppComponent {
parties: Observable<any[]>;

constructor() {
this.parties = Parties.find({}).zone();
}
}
What exactly does Parties.find({}).zone() do?