- Typescript-ize
- PR for turf-concave's mandatory units paramater
- Convert turf's tests to typescript and see if tests compile?
- Make 4 boxes
- When clicking on a box, create a filter for all 4 boxes, with this one being "active"
- Calculate valid "active" postcodes and create a new layer for each of them, or reuse given 10 layers, and hide as necessary