To change the datatype, you can access the inner list and set the corresponding property. Please check: http://webix.com/snippet/57acffa3
Webix has built-in solutions for the following datatypes:json, xml, csv andjsarray. As two last datatypes have no tags, the default parser will process the data with auto-generated keys:data0,data1, etc. andid (required in any dataset).
If it’s not enough for your use-case, check the following guide about creating a custom data driver.