I have not worked with React, but it's on my list of things to learn "when I have time". Thank you for the detailed write-up you did! I'll definitely be referring back to it.
The parcel drafter widget is sort of like the WAB equivalent of ArcGIS Pro's "Traverse" tool. It's used for drawing up legal descriptions.
You set a beginning point, then enter things like a bearing of "N 34°51'30" E" and a distance of "50.19", and it sketches a temporary line in the map. These lines can also have a radius value, defining a circular arc. The endpoint of that line is used as the beginning point of the next, and entering all the segments of a legal lets you visualize the boundary being described, see whether or not it closes, interactively reorder, add, and remove segments.
When you're done, the lines are all saved as features in a linked layer, and the bearing, distance, and curve information is stored in attributes on the line features. If the boundary closes, the tool also creates a polygon to represent the "parcel" being drafted, lets you add information to that parcel feature, and there is a relationship class between the parcels and their lines.
- Josh Carlson
Kendall County GIS