intersection and union function for arrays

[nahiyan-yasaar-selise]

To generate certain reports we are generating an html table but have to rely on triple nested loops. The generation involves both user input (multivalue) and checking the data source for whether records exist for that selection. For example: User selects in a prompt values A to P, but in the data source module, what exists are only records with values G to Z. Because of this, the nested loop still has to loop A to F just to check if data exists or not. This is unoptimal.

The solution involves two independent steps:

1. Find the array of unique values from the data source (i.e. G to Z) (feature request here)
2. Find intersection between this array and selection array

Ideally, assuming we have an array of existing values (G-Z), the intersection expression should return an array of values G-P so that we are only looping through G-P.

We did dedicate a portion of the workflow to manually figure out this intersection, but relying on this all the time is prone to errors.

Expression --> Desired output:
newArr = intersect(newArr, ["A", "B", "C", "D"], ["C", "D", "E"]) --> newArr = ["C", "D"]
newArr = union(newArr, ["A", "B", "C", "D"], ["C", "D", "E"]) --> newArr = ["A", "B", "C", "D", "E"]