On the Advanced tab of your HTTPInput node, select Parse Query String. This
option enables you to access the JSONP script prefix that is included
in the incoming URL, for example scriptFn, from the
local environment tree.
Insert the following code, as appropriate:
If your message flow uses a Compute node:
SET OutputRoot.JSON.Padding = InputLocalEnvironment.HTTP.Input.QueryString.jsonp;
SET OutputRoot.JSON.Data.objectName = 'thing1';