Angular Material 2 DataTable Sorting with nested objects

I have a normal Angular Material 2 DataTable with sort headers. All sort are headers work fine. Except for the one with an object as value. These doesn't sort at all.

For example:

 <!-- Project Column - This should sort!-->
    <ng-container matColumnDef="project.name">
      <mat-header-cell *matHeaderCellDef mat-sort-header> Project Name </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.project.name}} </mat-cell>
    </ng-container>

note the element.project.name

Here's the displayColumn config:

 displayedColumns = ['project.name', 'position', 'name', 'test', 'symbol'];

Changing 'project.name' to 'project' doesn't work nor "project['name']"

What am I missing? Is this even possible?

Here's a Stackblitz: Angular Material2 DataTable sort objects

Edit: Thanks for all your answers. I've already got it working with dynamic data. So I don't have to add a switch statement for every new nested property.

Here's my solution: (Creating a new DataSource which extends MatTableDataSource is not necessary)

export class NestedObjectsDataSource extends MatTableDataSource<MyObjectType> {

  sortingDataAccessor: ((data: WorkingHours, sortHeaderId: string) => string | number) =
    (data: WorkingHours, sortHeaderId: string): string | number => {
      let value = null;
      if (sortHeaderId.indexOf('.') !== -1) {
        const ids = sortHeaderId.split('.');
        value = data[ids[0]][ids[1]];
      } else {
        value = data[sortHeaderId];
      }
      return _isNumberValue(value) ? Number(value) : value;
    }

  constructor() {
    super();
  }
}

It was hard to find documentation on this, but it is possible by using sortingDataAccessor and a switch statement. For example:

@ViewChild(MatSort) sort: MatSort;

ngOnInit() {
  this.dataSource = new MatTableDataSource(yourData);
  this.dataSource.sortingDataAccessor = (item, property) => {
    switch(property) {
      case 'project.name': return item.project.name;
      default: return item[property];
    }
  };
  this.dataSource.sort = sort;
}

You can write a function in component to get deeply property from object. Then use it in dataSource.sortingDataAccessor like below

getProperty = (obj, path) => (
  path.split('.').reduce((o, p) => o && o[p], obj)
)

ngOnInit() {
  this.dataSource = new MatTableDataSource(yourData);
  this.dataSource.sortingDataAccessor = (obj, property) => this.getProperty(obj, property);
  this.dataSource.sort = sort;
}

columnDefs = [
  {name: 'project.name', title: 'Project Name'},
  {name: 'position', title: 'Position'},
  {name: 'name', title: 'Name'},
  {name: 'test', title: 'Test'},
  {name: 'symbol', title: 'Symbol'}
];

And in html

<ng-container *ngFor="let col of columnDefs" [matColumnDef]="col.name">
      <mat-header-cell *matHeaderCellDef>{{ col.title }}</mat-header-cell>
      <mat-cell *matCellDef="let row">
        {{ getProperty(row, col.name) }}
      </mat-cell>
  </ng-container>

The answer as given can even be shortened, no switch required, as long as you use the dot notation for the fields.

ngOnInit() {
  this.dataSource = new MatTableDataSource(yourData);

  this.dataSource.sortingDataAccessor = (item, property) => {
     if (property.includes('.')) return property.split('.').reduce((o,i)=>o[i], item)
     return item[property];
  };

  this.dataSource.sort = sort;
}

I use a generic method which allows you to use a dot.seperated.path with mat-sort-header or matColumnDef. This fails silently returning undefined if it cannot find the property dictated by the path.

function pathDataAccessor(item: any, path: string): any {
  return path.split('.')
    .reduce((accumulator: any, key: string) => {
      return accumulator ? accumulator[key] : undefined;
    }, item);
}

You just need to set the data accessor

this.dataSource.sortingDataAccessor = pathDataAccessor;

I like @Hieu_Nguyen solutions. I'll just add that if you use lodash in you project as I do then the solution translates to this:

import * as _ from 'lodash';

this.dataSource.sortingDataAccessor = _.get; 

No need to reinvent the deep property access.