const str = 'The sunset sets at twelve o clock.The sunset sets at twelve o clock.The sunset sets at twelve o clock.The sunset sets at twelve o clock.';

function reverseStringSplitReverse(str) {
    return str.split("").reverse().join("");
}

function reverseStringFor(str) {
    var newString = "";
    for (var i = str.length - 1; i >= 0; i--) {
        newString += str[i];
    }
    return newString;
}

function reverseStringRecursion(str) {
  if (str === "")
    return "";
  else
    return reverseStringRecursion(str.substr(1)) + str.charAt(0);
}