Angularfire: Query ordered by ascending / descending

[funnytao]

Hi,

I am learning Angular 2 recently and I find angularfire2 really useful and handy. However, I don't know whether there is a way to sort the query data by descending. Do I miss anything or it is just not an option for query? Thank you so much.

[lf-alves]

This is a very common issue for most firebase users who try any type of advanced querying. This issue has been discussed a lot in the past and there's a couple of different solutions for this problem, most of which were given by firebase team members.

You can check all the SO questions regarding this topic here

[funnytao]

Hi, I just don't want to make things get complicated, so I just write a pipe to sort and filter the data I want. Thank you so much.

[justme1]

https://github.com/angular/angularfire2/issues/283#issuecomment-231511751

[davideast]

This question should handle it: http://stackoverflow.com/questions/25611356/display-posts-in-descending-posted-order

[jdell64]

So, the solution is to make sure that you push the data in the order you will want later?

I am just checking, not passing judgement 😄

[jdell64]

Oh nm... found it... you can make a map.

[niojihy]

ref.orderBy('price', 'desc'));
ref.orderBy('price', 'asc'));

[Sireini]

@niojihy is this:
ref.orderBy('price', 'desc'));
ref.orderBy('price', 'asc'));

working for you?

[RHeckers]

This is how I solved it:
First I made a query in my service where I filter by date in milliseconds:

 getImages (): Observable<Image[]> {
this.imageCollection = this.asf.collection<Image>('/images', ref => ref.orderBy('time').startAt(1528445969388).endAt(9999999999999));
this.images = this.imageCollection.snapshotChanges().pipe(
  map(actions => actions.map(a => {
    const data = a.payload.doc.data() as Image;
    const id = a.payload.doc.id;
    return { id, ...data };
  }))
);
return this.images;

}

Then to get the newest date first I added this to my component where I call the method from my service:

let date = new Date;
let time = 9999999999999 - date.getTime();
console.log(time);

I pass the time let as the date. Since a newer date will be a bigger number to deduct from the 9999999999999, the newest date will turn up first in my query inside my service.

Hope this solved it for you