this.dataRows = res.data.items;

<ngx-datatable
            class="bootstrap"
            [rows]="dataRows"
            [columns]="dataColumns"
            [columnMode]="'force'"
            [headerHeight]="50"
            [selectionType]="'single'"
            [selected]="selected"
            (select)="recordSelected()"
            [messages]="{emptyMessage: 'Data not found!', totalMessage: 'total'}"
            [count]="totalItems"
            >
        </ngx-datatable>

core.js:1350 ERROR TypeError: Cannot convert undefined or null to object