Unobfuscated version of HATETRIS's default AI

hatetris.js

function construct(getNextStates) {
	return function ai(currentState) {
		const pieces = [
			{name:"S", annoyance:7},
			{name:"Z", annoyance:6},
			{name:"O", annoyance:5},
			{name:"I", annoyance:4},
			{name:"L", annoyance:3},
			{name:"J", annoyance:2},
			{name:"T", annoyance:1},
		];
		for(const piece of pieces) {
			const wellHeights = getNextStates(piece.name, currentState)
			                    .map(getWellHeight);
			piece.bestWellHeight = Math.min(...wellHeights);
		}
		// Find the piece that, at best, still gives the highest well height.
		// Tie-break by selecting the most annoying piece.
		pieces.sort((a,b)=>a.bestWellHeight - b.bestWellHeight || a.annoyance - b.annoyance);
		return pieces[0].name;
	}
}