Angular: MatSort not working when using object inside datasource

Question

I have an angular 6 application which has a Mat Table. Data for the table is populated like below. Sorting works for the fields position and name, but not weight and symbol which are part of the detail object. I have also tried naming the columns like detail.weight in displayedColumns and matColumnDef but with no luck. Please advise what am I doing wrong ?

const ELEMENT_DATA: PeriodicElement[] = [
  {position: 1, name: 'Hydrogen', detail: {weight: 4.0026, symbol: 'He'}},
  {position: 2, name: 'Helium', detail: {weight: 4.0026, symbol: 'He'}},
]

displayedColumns: string[] = ['position', 'name', 'weight', 'symbol'];

Template

 <ng-container matColumnDef="weight">
    <th mat-header-cell *matHeaderCellDef mat-sort-header> Weight </th>
    <td mat-cell *matCellDef="let element"> {{element.detail.weight}} </td>
  </ng-container>

Here is the stackblitz url for the issue
https://stackblitz.com/edit/angular-kumdeq

Answer 1

Use sortingDataAccessor, which

Allows for sort customization by overriding sortingDataAccessor, which defines how data properties are accessed.

Add this code snippet inside ngOnInit:

   this.dataSource.sortingDataAccessor = (item, property) => {
     switch (property) {
       case 'weight': return  item.detail.weight;
       case 'symbol': return  item.detail.symbol;
       default: return item[property];
  }

Link: https://stackblitz.com/edit/angular-kumdeq-z4bags