Extremely fast Game of Life implementation in 30 lines of JavaScript

gameOfLife.js

function gameOfLife(pop) {
	const newpop = {};
	for (const coord in pop) {
		const parts = coord.split(',');
		const x = Number(parts[0]);
		const y = Number(parts[1]);
		for (let dx = -1; dx <= 1; ++dx) {
			for (let dy = -1; dy <= 1; ++dy) {
				newpop[`${x+dx},${y+dy}`] = true;
			}
		}
	}
	for (const coord in newpop) {
		const parts = coord.split(',');
		const x = Number(parts[0]);
		const y = Number(parts[1]);
		let neighbors = 0;
		for (let dx = -1; dx <= 1; ++dx) {
			for (let dy = -1; dy <= 1; ++dy) {
				if (!(dx === 0 && dy === 0) && pop[`${x+dx},${y+dy}`]) {
					neighbors++;
				}
			}
		}
		if (!(neighbors === 3 || (pop[coord] && neighbors === 2))) {
			delete newpop[coord];
		}
	}
	return newpop;
}