JS随机生成字符串的方法

const randomStr = (len) => {
	let str = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
	let result = "";
	while(len) {
		let index = Math.floor(Math.random() * str.length);
		result += str[index];
		--len;
	}
	return result;
}