git.squeep.com Git - squeep-base64url/blob - lib/base64url.js

   1 'use strict';
   2
   3 const reEqual = /=/g;
   4 const rePlus = /\+/g;
   5 const reSlash = /\//g;
   6 const reDash = /-/g;
   7 const reUnder = /_/g;
   8 const blockSize = 4;
   9
  10 /**
  11  * Convert Base64 to Base64URL.
  12  * @param {String} input
  13  * @returns {String}
  14  */
  15 const base64ToBase64URL = (input) => {
  16   return input
  17     .replace(reEqual, '')
  18     .replace(rePlus, '-')
  19     .replace(reSlash, '_');
  20 };
  21
  22 /**
  23  * Convert Base64URL to normal Base64.
  24  * @param {String} input
  25  * @returns {String}
  26  */
  27 const base64URLToBase64 = (input) => {
  28   return base64RePad(input)
  29     .replace(reDash, '+')
  30     .replace(reUnder, '/');
  31 };
  32
  33 /**
  34  * Add any missing trailing padding which may have been removed from Base64URL encoding.
  35  * @param {String} input
  36  */
  37 const base64RePad = (input) => {
  38   const lastBlockSize = input.length % blockSize;
  39   if (lastBlockSize) {
  40     const missing = blockSize - lastBlockSize;
  41     return input + '='.repeat(missing);
  42   }
  43   return input;
  44 };
  45
  46 module.exports = {
  47   base64ToBase64URL,
  48   base64URLToBase64,
  49   base64RePad,
  50 }