Solution for : How to check if subscribed data is an Array of object or an object ?

If you want to check if the data returned by our service is an Array or a simple object we can use the Array.isArray(**) function

Example :

 this._Service.getList().subscribe(
      (data) => {
        if (Array.isArray(data)) {
           this.dataSource =  new MatTableDataSource(data);
}
 else {
          this.dataSource = new MatTableDataSource([data]);
          }

here we added [data] when the service returns an object to make sure that we are affecting an array to our dataSource