I'm currently using turf.js to split a polygon into rectangles of a specified length & width. It's a modification of the squareGrid function: https://turfjs.org/docs/#squareGrid
I'm hoping there is a way to achieve this using the ArcGIS JS API. It would avoid some messy converting code to get the polygon into GeoJSON for Turf.js to process.
Does anyone have any suggestions on where to look?