Shortens a guid from 36 characters to (22-24) characters

base64.ts

// Inspired By
// https://stackoverflow.com/questions/6213227/fastest-way-to-convert-a-number-to-radix-64-in-javascript

// Haven't Fully Tested or implemented in a prod environment

// Generate Random Value matching a guid
const Guid = (): string => {
  return 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx'.replace(/[x]/gi, () => {
    const crypto = require('crypto');
    const id = crypto.randomBytes(16).toString("hex")[5];
    return id;
  });
};

const bits = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz._~';

const encode = (value: number) => {
  if (isNaN(Number(value)) || value == null || value === Number.POSITIVE_INFINITY) throw "Not a valid number";
  if (value < 0) throw "Not a positive number."

  let bit;
  let remainder = value;
  let result = '';

  while (remainder !== 0) {
    bit = remainder % bits.length;
    result = bits.charAt(bit) + result;
    remainder = Math.floor(remainder / bits.length);
    //console.log(bit, result, remainder);
  }

  return result;
}

const decode = (value: string) => {
  const chars = value.split('');
  let nResult = 0;
  chars.forEach((v, i) => {
    nResult = nResult * bits.length + bits.indexOf(v);
  });
  return nResult;
}

export const Id2Guid = (value: string) => {
  const parts = value.split('-');
  let groups: string[] = [];

  parts.forEach(n => {
    groups.push(decode(n).toString(16));
  });
  groups[0] = groups[0].padStart(8, '0');
  groups[1] = groups[1].padStart(12, '0').replace(/(\w{4})(\w{4})(\w{4})/gm, `$1-$2-$3`);
  groups[2] = groups[2].padStart(12, '0');
  return groups.join('-');
}

export const Guid2Id = (guid: string) => {
  if (guid.length !== 36) throw "Guid length is not 36";

  const groups = guid.split('-');

  if (groups.length !== 5) throw "not a valid guid";

  const result = [
    encode(parseInt('0x' + groups[0])),
    encode(parseInt('0x' + groups[1] + groups[2] + groups[3])),
    encode(parseInt('0x' + groups[4]))
  ];

  return result.join('-');
}


// Test
for (var i = 0; i < 100; i++) {
  const guid = Guid();
  const encoded = Guid2Id(guid);
  const decoded = Id2Guid(encoded);
  console.log(guid, encoded, encoded.length, decoded, decoded.length, guid === decoded);
}