SOURCE

function sort(arr){
	if(arr.length === 1){
		return arr;
	}
	//分成两部分
	let mid = Math.floor(arr.length/2);
	let [part1,part2] = [sort(arr.slice(0,mid)),sort(arr.slice(mid))];
	//对比+合并
	let result = [];
	while(part1.length>0 && part2.length>0){
		result.push((part1[0]<part2[0]?part1.shift():part2.shift()));
	}
	return [...result,...part1,...part2];
}

console.log(sort([1,7,6,8,3]))