The transform documentation listed here is outdated and is nonger actively maintained. Please refer to https://developer.sailpoint.com/idn/docs/transforms for IdentityNow Transform documentation.
In order to use the "now" keyword, I had to specify an empty input. A small tweak to Example 1 from above:
{"attributes": {"input": "","expression": "now-5d/d","roundUp": false},"type": "dateMath","id": "Test Date Math Transform"}
Please note that when your input is in the ISO8601 format and you perform a DateMath transform the output is not necessarily in ISO8601 format it could be something like yyyy-MM-dd'T'HH:mm'Z' . This needs to be highlighted clearly in the document.
