Datewise group data from firebase in angular 8

I want to display the list grouping by date in angular 8. Example like this image below but I don't have any idea how to make it working. I am fetching the data from firestore in angular 8.

scan-history.ts

 async lastScan(){
    let fid = 432820344;
    let pid = 580676108;
    var unixtimestamp = new Date(new Date().setDate(new Date().getDate() - 2)).valueOf();
    await this.api.getB2ChStockMoves(fid.toString()).then(async data => {
      console.log(data);
       this.lastScanData = data;
      }).catch(error => {
      console.log(error);
    });
  }

api.service.ts

     public getB2ChStockMoves(freezerid): Promise<any> {
        return new Promise<any>((resolve, reject) => {
    this.adb.collection('stockmoves_channel',ref=>ref.where('freezerid','==',freezerid).orderBy('unixtimestamp','desc')).get().subscribe((stocks) => {
        var data = stocks.docs.map(element => {
        item.product.get().then(function (doc) {
        item.product = doc.data();
     });
        item.id = element.id;
        return item;
     });
       resolve(data);
     }, error => {
       reject(error);
     })
    });
   } 

API response data

I am storing the field createdAt so that I can group date based on date. But I am unable to proceed further.