I think columns need correction for GridColumn interface:
interface GridColumn {
aggregates?: any;
attributes?: any;
columns?: any;
//I think this should be GridColumn[] not any
command?: GridColumnCommandItem[];
encoded?: boolean;
field?: string;
filterable?: boolean|GridColumnFilterable;
footerAttributes?: any;
footerTemplate?: string|Function;
format?: string;
groupable?: boolean;
groupHeaderTemplate?: string|Function;
groupFooterTemplate?: string|Function;
headerAttributes?: any;
headerTemplate?: string|Function;
hidden?: boolean;
locked?: boolean;
lockable?: boolean;
minScreenWidth?: number;
sortable?: boolean|GridColumnSortable;
template?: string|Function;
title?: string;
width?: string|number;
values?: any;
menu?: boolean;
}