Counts how many days left until the deadline.
By the way, here's a query to collect all deadlines within a range in case you need it.
#+BEGIN_QUERY
{
:title "all deadline or schedule within 21 days"
:query [:find (pull ?block [*])
:in $ ?start ?next
:where
(or
[?block :block/scheduled ?d]
[?block :block/deadline ?d]
)
[(> ?d ?start)]
[(< ?d ?next)]
]
:inputs [:today :21d-after]
}
#+END_QUERY
This plugin is intended to be minimal. For advanced features like automatic updating (timer), you may take a look at logseq-plugin-interval-hints.