asksuite-core/util/IntEncoder.js

const defaultDictionary = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
const regex = '(?:^|\\s)#([a-zA-Z0-9]+(?:-?[a-zA-Z0-9]+))(?:$|\\s)';

module.exports = (dictionary = defaultDictionary) => {
  const encode = value => {
    if (!Number.isInteger(value)) {
      return null;
    }

    const result = [];
    let remainder = value;
    do {
      const index = remainder % dictionary.length;
      remainder = Math.floor(remainder / dictionary.length);

      result.unshift(dictionary.charAt(index));
    } while (remainder > 0);
    return result.join('');
  };

  const decode = value => {
    if (!validate(value)) {
      return null;
    }

    value = String(value);
    let result = 0;
    for (let i = 0; i < value.length; i++) {
      const index = dictionary.indexOf(value.charAt(value.length - i - 1));

      result += index * Math.pow(dictionary.length, i);
    }
    return result;
  };

  const validate = value => {
    if (value !== 0 && !value) {
      return false;
    }

    if (Number.isInteger(value)) {
      return true;
    }

    for (let i = 0; i < value.length; i++) {
      if (dictionary.indexOf(value.charAt(i)) === -1) {
        return false;
      }
    }

    return true;
  };

  const extract = value => {
    const result = value.match(new RegExp(regex));

    if (!result || !result[1]) return null;

    const resultWithoutHash = result[1];
    const [encodedValue1, encodedValue2] =
      resultWithoutHash.indexOf('-') >= 0 ? resultWithoutHash.split('-') : [resultWithoutHash, ''];

    if (validate(encodedValue1)) {
      if (encodedValue2.length && validate(encodedValue2))
        return `${encodedValue1}-${encodedValue2}`;

      return encodedValue1;
    }

    return null;
  };

  return {
    encode,
    decode,
    validate,
    extract,
  };
};