Time left until due date
Return the duration between the current date and the due date of the current work item in days.
Configuration
Create a Custom smart number field and use the General parsing mode.
Expression
%{{issue.dueDate} != null ? max({issue.dueDate} - {system.currentDateTime}, 0) / DAY
: null}
If the resulting number from the expression contains too many decimal numbers, feel free to select one of the available display formats or to configure it manually.
Format
Default
Used parser functions
The links lead to the JWTC documentation because the parser functions are shared functionalities.