More Zeros Than Ones (6kyu)

function moreZeros(s) {
  let string = s;
  let arr = string.split("");
  let uniq = new Set();
  arr.forEach(letter => {
    uniq.add(letter);
  });
  let data = Array.from(uniq);

  const turnToBinary = letter => {
    let code = letter.charCodeAt();
    return code.toString(2);
  };

  const formatBinary = binary => {
    let index = binary.indexOf("1");
    let binStr = binary;
    if (index !== 0) {
      binStr = binStr.substring(index);
    }
    return binStr;
  };

  const evalBinary = binary => {
    let binStr = binary;
    let zeros = binStr.split("").filter(letter => letter === "0");
    return zeros.length > binStr.length - zeros.length;
  };

  let output = [];
  data.forEach(letter => {
    let currentBin = turnToBinary(letter);
    if (evalBinary(formatBinary(currentBin))) {
      output.push(letter);
    }
  });

  return output;
}