export class TableExportDemo implements OnInit {

    cars: Car[];

    selectedCars: Car[];

    cols: any[];

    constructor(private carService: CarService) { }

    ngOnInit() {
        this.carService.getCarsSmall().then(cars => this.cars = cars);

        this.cols = [
            { field: 'vin', header: 'Vin' },
            { field: 'year', header: 'Year' },
            { field: 'brand', header: 'Brand' },
            { field: 'color', header: 'Color' }
        ];
    }
}

<p-table #dt [columns]="cols" [value]="cars" selectionMode="multiple" [(selection)]="selectedCars">
    <ng-template pTemplate="caption">
        <div class="ui-helper-clearfix">
            <button type="button" pButton icon="fa-file-o" iconPos="left" label="All Data" (click)="dt.exportCSV()" style="float:left"></button>
            <button type="button" pButton icon="fa-file" iconPos="left" label="Selection Only" (click)="dt.exportCSV({selectionOnly:true})" style="float:right"></button>
        </div>
    </ng-template>
    <ng-template pTemplate="header" let-columns>
        <tr>
            <th *ngFor="let col of columns">
                {{col.header}}
            </th>
        </tr>
    </ng-template>
    <ng-template pTemplate="body" let-rowData let-columns="columns">
        <tr [pSelectableRow]="rowData">
            <td *ngFor="let col of columns">
                {{rowData[col.field]}}
            </td>
        </tr>
    </ng-template>
</p-table>