How to check the length of an Observable array

In my Angular 2 component I have an Observable array

list$: Observable<any[]>;

In my Template I have

<div *ngIf="list$.length==0">No records found.</div>

<div *ngIf="list$.length>0">
    <ul>
        <li *ngFor="let item of list$ | async">item.name</li>
    </ul>
</div>

But list$.length doesn't work with in case of Observable array.

Update:

It seems that (list$ | async)?.length gives us the length but the below code still doesn't work:

<div>
    Length: {{(list$ | async)?.length}}
    <div *ngIf="(list$ | async)?.length>0">
        <ul>
            <li *ngFor="let item of (list$ | async)">
                {{item.firstName}}
            </li>
        </ul>
    </div>
</div>

Can anyone please guide how do I check length of Observable array.

You can use the | async pipe:

<div *ngIf="(list$ | async)?.length==0">No records found.</div>

Update - 2021-2-17

<ul *ngIf="(list$| async) as list; else loading">
   <li *ngFor="let listItem of list">
      {{ listItem.text }}
   </li>
</ul>

<ng-template #loading>
  <p>Shows when no data, waiting for Api</p>
  <loading-component></loading-component>
</ng-template>

Update - Angular Version 6:

If you are loading up a css Skeleton you can use this. If the array has no items it will display the css template. If there is data then fill out the ngFor.

<ul *ngIf="(list$| async)?.length > 0; else loading">
   <li *ngFor="let listItem of list$| async">
      {{ listItem.text }}
   </li>
</ul>

<ng-template #loading>
  <p>Shows when no data, waiting for Api</p>
  <loading-component></loading-component>
</ng-template>

A solution for .ts-Files:

     this.list.subscribe(result => {console.log(result.length)});

For Angular 4+, try this

<div *ngIf="list$ | async;let list">
    Length: {{list.length}}
    <div *ngIf="list.length>0">
        <ul>
            <li *ngFor="let item of list">
                {{item.firstName}}
            </li>
        </ul>
    </div>
</div>

While this answer is correct

<div *ngIf="(list$ | async)?.length === 0">No records found.</div>

Keep in mind that if you are using http client to call backend (in most cases you do) you will get duplicate calls to your API if you have more that one list$ | async. This is because each | async pipe will create new subscriber to your list$ observable.

Can be shortened as well:

<div *ngIf="!(list$ | async)?.length">No records found.</div>

Just use the exclamation mark before the parenthesis.

This is what worked for me -

*ngIf="!photos || photos?.length===0"

I am getting my data from httpClient async.

All the other options here didn't work for me which was disappointing. Especially the sexy (list$ | async) pipe.

Basa..

I had this issue with Observable<Customer[]> (initialized in a constructor) saying "object is possibly undefined" when trying to hide container div when arr length is empty So I had it like this: <div *ngIf="(similarCustomers$ | async)?.length > 0">

My co-worker solved it by doing this:

<div *ngIf="(similarCustomers$ | async) as similarCustomers">
  <ng-container *ngIf="similarCustomers.length > 0">

ionic 4

<div *ngIf="(items | async)?.length==0">No records found.</div>

it worked when i removed the $ sign