// Single dot:
if (str[str.length-1] === ".")
    str = str.slice(0,-1);
// Multiple dots:
while (str[str.length-1] === ".")
    str = str.slice(0,-1);
// Single dot, regex:
str = str.replace(/\.$/, "");
// Multiple dots, regex:
str = str.replace(/\.+$/, "");