SAP UI5 application throws an error while using Tree map

Note that SAP UI5 1.14 version supports Tree map and older version like 1.12 doesn’t have Tree map. You can try using below link: http://jsbin.com/aku-test-treemap-exists/1/edit?html,output

It returns the code of tree map constructor, try loading your own copy sap-ui-core-js of UI5.