To include a numeric range facet, add to your HTML

 <div ex:role="facet" 
   ex:facetClass="NumericRange"
   ex:expression=".age" 
   ex:interval="10">
 </div>

Replace .age with the appropriate expression for your exhibit. Replace 10 with the size of the intervals that you want the values to be grouped into. The default is 10.

Remember to assign valueType:number to your data in order to use the NumericRange facet:

properties: { 'age': { valueType: "number" } }

Other settings supported include:

setting name	type of value	default	choices	meaning
ex:facetLabel	text			what to show in the header of the facet
ex:height	text			height of the facet's body, e.g., "20em", "200px"