Angular - Objects as Select Option Values
It is the [compareWith] directive. Angular.io is down at the moment, so I will ink to this medium article for reference.
HTML
<mat-select placeholder="Fruit" [(ngModel)]="item.fruit" [compareWith]="objectComparisonFunction"> <mat-option *ngFor="let option of options" [value]="option">{{option.label}}</mat-option></mat-select>TypeScript
public objectComparisonFunction = function( option, value ) : boolean { return option.id === value.id; }