Nested object / array is great for finding stuff, seems like it would also be a useful short hand to provide a transformation of these values into a flat Array.
something like...
let hex = Polymer.SimpleColorsUtility.instance.hexCodes;
let colors = [];
for (var i in hex) {
for (var j in hex) {
colors.push(hex[i][j]);
}
}
This way you could call 1 function / value and get a (flat) list of valid colors for selection or testing against.