text: define([],function(){
    'use strict'
    var exports = {};
  
    exports.byteLength = byteLength
    exports.toByteArray = toByteArray
    exports.fromByteArray = fromByteArray
  
    var lookup = []
    var revLookup = []
    var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array
  
    var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
    for (var i = 0, len = code.length; i < len; ++i) {
      lookup[i] = code[i]
      revLookup[code.charCodeAt(i)] = i
    }
  
    // Support decoding URL-safe base64 strings, as Node.js does.
    // See: https://en.wikipedia.org/wiki/Base64#URL_applications
    revLookup['-'.charCodeAt(0)] = 62
    revLookup['_'.charCodeAt(0)] = 63
  
    function getLens (b64) {
      var len = b64.length
  
      if (len % 4 > 0) {
        throw new Error('Invalid string. Length must be a multiple of 4')
      }
  
      // Trim off extra bytes after placeholder bytes are found
      // See: https://github.com/beatgammit/base64-js/issues/42
      var validLen = b64.indexOf('=')
      if (validLen === -1) validLen = len
  
      var placeHoldersLen = validLen === len
        ? 0
        : 4 - (validLen % 4)
  
      return [validLen, placeHoldersLen]
    }
  
    // base64 is 4/3 + up to two characters of the original data
    function byteLength (b64) {
      var lens = getLens(b64)
      var validLen = lens[0]
      var placeHoldersLen = lens[1]
      return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
    }
  
    function _byteLength (b64, validLen, placeHoldersLen) {
      return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
    }
  
    function toByteArray (b64) {
      var tmp
      var lens = getLens(b64)
      var validLen = lens[0]
      var placeHoldersLen = lens[1]
  
      var arr = new Arr(_byteLength(b64, validLen, placeHoldersLen))
  
      var curByte = 0
  
      // if there are placeholders, only get up to the last complete 4 chars
      var len = placeHoldersLen > 0
        ? validLen - 4
        : validLen
  
      var i
      for (i = 0; i < len; i += 4) {
        tmp =
          (revLookup[b64.charCodeAt(i)] << 18) |
          (revLookup[b64.charCodeAt(i + 1)] << 12) |
          (revLookup[b64.charCodeAt(i + 2)] << 6) |
          revLookup[b64.charCodeAt(i + 3)]
        arr[curByte++] = (tmp >> 16) & 0xFF
        arr[curByte++] = (tmp >> 8) & 0xFF
        arr[curByte++] = tmp & 0xFF
      }
  
      if (placeHoldersLen === 2) {
        tmp =
          (revLookup[b64.charCodeAt(i)] << 2) |
          (revLookup[b64.charCodeAt(i + 1)] >> 4)
        arr[curByte++] = tmp & 0xFF
      }
  
      if (placeHoldersLen === 1) {
        tmp =
          (revLookup[b64.charCodeAt(i)] << 10) |
          (revLookup[b64.charCodeAt(i + 1)] << 4) |
          (revLookup[b64.charCodeAt(i + 2)] >> 2)
        arr[curByte++] = (tmp >> 8) & 0xFF
        arr[curByte++] = tmp & 0xFF
      }
  
      return arr
    }
  
    function tripletToBase64 (num) {
      return lookup[num >> 18 & 0x3F] +
        lookup[num >> 12 & 0x3F] +
        lookup[num >> 6 & 0x3F] +
        lookup[num & 0x3F]
    }
  
    function encodeChunk (uint8, start, end) {
      var tmp
      var output = []
      for (var i = start; i < end; i += 3) {
        tmp =
          ((uint8[i] << 16) & 0xFF0000) +
          ((uint8[i + 1] << 8) & 0xFF00) +
          (uint8[i + 2] & 0xFF)
        output.push(tripletToBase64(tmp))
      }
      return output.join('')
    }
  
    function fromByteArray (uint8) {
      var tmp
      var len = uint8.length
      var extraBytes = len % 3 // if we have 1 byte left, pad 2 bytes
      var parts = []
      var maxChunkLength = 16383 // must be multiple of 3
  
      // go through the array every three bytes, we'll deal with trailing stuff later
      for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
        parts.push(encodeChunk(
          uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)
        ))
      }
  
      // pad the end with zeros, but make sure to not forget the extra bytes
      if (extraBytes === 1) {
        tmp = uint8[len - 1]
        parts.push(
          lookup[tmp >> 2] +
          lookup[(tmp << 4) & 0x3F] +
          '=='
        )
      } else if (extraBytes === 2) {
        tmp = (uint8[len - 2] << 8) + uint8[len - 1]
        parts.push(
          lookup[tmp >> 10] +
          lookup[(tmp >> 4) & 0x3F] +
          lookup[(tmp << 2) & 0x3F] +
          '='
        )
      }
  
      return parts.join('')
    }
  
    return exports;
  });