Invalid argument '[object Object]' for pipe 'AsyncPipe'

At the HTML of page

<ion-item *ngFor="#item of post | async" >
    {{item}}
</ion-item>

and inside .ts post is an array containing data coming from firebase(as list of objects) like this:

this.http.request("https://taskionic
.firebaseio.com /firebaseList.json").subscribe((res) => {
           this.post = res.json(); }

I usually have to wrap my pipe operations in parentheses to force proper evaluation order. Try:

*ngFor="#item of (post | async)"