hexToRgb.js

function getRgb(hex) {
  try {
    if (
      typeof hex !== "string" ||
      (hex.length !== 7 && hex.length !== 4) ||
      hex[0] !== "#"
    ) {
      throw {
        name: "Problem",
        message: "This is not a proper string",
      };
    } else {
      hex = hex.split("");
      let temp = hex.shift();
      temp = hex.join("");

      if (hex.length === 3) {
        temp = temp.split("").map((item) => item + item);
        temp = temp.join("");
      }

      temp = temp.match(/.{1,2}/g);

      let forrmatted = temp.map((item) => parseInt(`0x${item}`));

      return `rgb(${forrmatted.join(", ")})`;
    }
  } catch (e) {
    console.error("Problem with converting: " + e.message);
  }
}

console.log(getRgb("#FFFFFF"));
console.log(getRgb("#FDA"));