Promise.all behavior with RxJS Observables?

Question

In Angular 1.x I would sometimes need to make multiple http requests and do something with all the responses. I would throw all the promises in an array and call Promise.all(promises).then(function (results) {...}).

Angular 2 best practices seem to point towards the use of RxJS's Observable as a replacement to promises in http requests. If I have two or more different Observables created from http requests, is there an equivalent to Promise.all()?

Answer 1

The more straightforward alternative for emulating Promise.all is to use the forkJoin operator (it starts all observables in parallel and join their last elements):

• documentation
• related link: Cf. RxJS: concat three promises, distinguish results

A bit out of scope, but in case it helps, on the subject of chaining promises, you can use a simple flatMap : Cf. RxJS Promise Composition (passing data)