Cell interface is a base for built-in cell templates and your own, it has only one necessary property - type.
Definition
interface Cell {
    type: string;
    nonEditable?: boolean;
    groupId?: Id;
    style?: CellStyle;
    className?: string;
}Properties
| Properties | Type | Properties description | 
|---|---|---|
| type | string | Name of cell type, must be unique | 
| nonEditable? | boolean | Makes cell non editable - this property takes precedence over cell templating | 
| groupId? | Id | Idof group to which this cell belongs to | 
| style? | CellStyle | Allowed style properties contained in CellStyleinterface | 
| className? | string | Additional CSS classes | 
| colspan? | number | Specifies the number of columns a cell should span | 
| rowspan? | number | Specifies the number of rows a cell should span |