Encode and decode UUIDs into URL-safe Base 64

urlUuid.js

// converts a UUID to a URL-safe version of base 64.
const encode = uuid => {
  const stripped = uuid.replace(/-/g, ""); // remove dashes from uuid
  const true64 = btoa(
    String.fromCharCode.apply(
      null,
      stripped
        .replace(/\r|\n/g, "")
        .replace(/([\da-fA-F]{2}) ?/g, "0x$1 ")
        .replace(/ +$/, "")
        .split(" ")
    )
  ); // turn uuid into base 64
  const url64 = true64.replace(/\//g, "_").replace(/\+/g, "-"); // replace non URL-safe characters
  return url64;
};

// takes a URL-safe version of base 64 and converts it back to a UUID.
const decode = url64 => {
  const true64 = url64.replace(/_/g, "/").replace(/-/g, "+"); // replace url-safe characters with base 64 characters
  const raw = atob(true64); // decode the raw base 64 into binary buffer. 

  let hex = ""; // create a string of length 0
  let hexChar; // mostly because you don't want to initialize a variable inside a loop.
  for (let i = 0, l = raw.length; i < l; i++) {
    hexChar = raw.charCodeAt(i).toString(16); // get the char code and turn it back into hex.
    hex += hexChar.length === 2 ? hexChar : "0" + hexChar; // append hexChar as 2 character hex. 
  }
  hex = hex.toLowerCase(); // standardize.
  // pad zeroes at the front of the UUID.
  while (hex.length < 32) {
    hex = "0" + hex;
  }
  // add dashes for 8-4-4-4-12 representation 
  const uuid = hex.replace(/(.{8})(.{4})(.{4})(.{4})(.{12})/, "$1-$2-$3-$4-$5");
  return uuid;
};

const urlUuid = { encode, decode };

export default urlUuid