base32

class base32 {
  encode(input) {
    const base32chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
    let output = "";
    let buffer = 0;
    let bitsLeft = 0;

    for (let i = 0; i < input.length; i++) {
      buffer = (buffer << 8) | input.charCodeAt(i);
      bitsLeft += 8;

      while (bitsLeft >= 5) {
        output += base32chars.charAt((buffer >> (bitsLeft - 5)) & 31);
        bitsLeft -= 5;
      }
    }

    if (bitsLeft > 0) {
      output += base32chars.charAt((buffer << (5 - bitsLeft)) & 31);
    }

    return output.padEnd(Math.ceil(output.length / 8) * 8, "=");
  }

  decode(input) {
    const base32chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
    const cleanInput = input.replace(/=/g, "");
    let buffer = 0;
    let bitsLeft = 0;
    let output = "";

    for (let i = 0; i < cleanInput.length; i++) {
      buffer = (buffer << 5) | base32chars.indexOf(cleanInput.charAt(i));
      bitsLeft += 5;

      if (bitsLeft >= 8) {
        output += String.fromCharCode((buffer >> (bitsLeft - 8)) & 255);
        bitsLeft -= 8;
      }
    }

    return output;
  }

  matches(input) {
    const base32Regex = /^[A-Z2-7]{10,}=*$/;
    const result = base32Regex.exec(input);
    if (result && result[0].length % 8 === 0) {
      return result;
    }
    return null;
  }
}