happy-number_0526.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>happy-number</title>
  </head>
  <body></body>
  <script>
    /**
     * @param {number} n
     * @return {boolean}
     */
    var isHappy = function (n) {
      let count = 0;

      const loop = (num) => {
        let rResult = 0;
        num = (num + "").split("").map((s) => parseInt(s));

        for (let i = 0; i < num.length; i++) {
          rResult = rResult + Math.pow(num[i], 2);
        }

        if (rResult == 1) {
          return rResult;
        } else {
          count++;
          return count > 100 ? false : loop(rResult);
        }
      };

      return n < 1 ? false : loop(n);
    };
  </script>
</html>