There is no function in expression builder which can work as
join for an array.
The expected functionality of join function is to convert the array in string by joining the array element with the 2nd argument passed. Basically the functionality should be opposite of split.
only these functions are there:
Ex: arr = [1, 2, 3, 4]
join(arr, ',') => "1,2,3,4"
For achieving the same functionality, I have to do a work around with reduce and rtrim.
rtrim(toString(reduce(arr, "", #acc + ',' + #item, #result)), ",")
This leads to long nested functions if I have to use this inside another function.