Accumulating date diffs using Automations

[Aaron Axisa]

Hello

I am setting a field (type text) as a diff 

"Blocked": "{{issue.Due Date.diff(now)}}"

I would then like to increment this diff again , so roughly:

"Blocked":"{{issue.Blocked .insertfunctionhere (issue.Due Date.diff(now))}""

Eg:

Original gets set to "3d 5s"

Then it gets incremented by another 1d, to result in the field being set "4d 5s"
How can I increment the field since it doesn't seem to be parsable as a date itself.