text: var Filters = {}
  var encode
  
  Filters.Base64Filter = (function () {
    var Base64Filter = {}
  
    // constants
    var b64chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
    var b64tab = (function (bin) {
      var t = {}
      for (var i = 0, l = bin.length; i < l; i++) t[bin.charAt(i)] = i
      return t
    })(b64chars)
    var fromCharCode = String.fromCharCode
    // encoder stuff
    var cbUtob = function (c) {
      var cc
      if (c.length < 2) {
        cc = c.charCodeAt(0)
        return cc < 0x80 ? c : cc < 0x800 ? (fromCharCode(0xc0 | (cc >>> 6)) + fromCharCode(0x80 | (cc & 0x3f))) : (fromCharCode(0xe0 | ((cc >>> 12) & 0x0f)) + fromCharCode(0x80 | ((cc >>> 6) & 0x3f)) + fromCharCode(0x80 | (cc & 0x3f)))
      } else {
        cc = 0x10000 + (c.charCodeAt(0) - 0xD800) * 0x400 + (c.charCodeAt(1) - 0xDC00)
        return (fromCharCode(0xf0 | ((cc >>> 18) & 0x07)) + fromCharCode(0x80 | ((cc >>> 12) & 0x3f)) + fromCharCode(0x80 | ((cc >>> 6) & 0x3f)) + fromCharCode(0x80 | (cc & 0x3f)))
      }
    }
    var reUtob = /[\uD800-\uDBFF][\uDC00-\uDFFFF]|[^\x00-\x7F]/g
    var utob = function (u) {
      return u.replace(reUtob, cbUtob)
    }
    var cbEncode = function (ccc) {
      var padlen = [0, 2, 1][ccc.length % 3]
      var ord = ccc.charCodeAt(0) << 16 | ((ccc.length > 1 ? ccc.charCodeAt(1) : 0) << 8) | ((ccc.length > 2 ? ccc.charCodeAt(2) : 0))
      var chars = [b64chars.charAt(ord >>> 18), b64chars.charAt((ord >>> 12) & 63), padlen >= 2 ? '=' : b64chars.charAt((ord >>> 6) & 63), padlen >= 1 ? '=' : b64chars.charAt(ord & 63)]
      return chars.join('')
    }
    var btoa = function (b) {
      return b.replace(/[\s\S]{1,3}/g, cbEncode)
    }
    var _encode = function (u) {
      return btoa(utob(u))
    }
    encode = function (u, urisafe) {
      return !urisafe ? _encode(String(u)) : _encode(String(u)).replace(/[+\/]/g,
        function (m0) {
          return m0 === '+' ? '-' : '_'
        }).replace(/=/g, '')
    }
    // decoder stuff
    var reBtou = new RegExp(['[\xC0-\xDF][\x80-\xBF]', '[\xE0-\xEF][\x80-\xBF]{2}', '[\xF0-\xF7][\x80-\xBF]{3}'].join('|'), 'g')
    var cbBtou = function (cccc) {
      switch (cccc.length) {
        case 4:
          var cp = ((0x07 & cccc.charCodeAt(0)) << 18) | ((0x3f & cccc.charCodeAt(1)) << 12) | ((0x3f & cccc.charCodeAt(2)) << 6) | (0x3f & cccc.charCodeAt(3))
          var offset = cp - 0x10000
          return (fromCharCode((offset >>> 10) + 0xD800) + fromCharCode((offset & 0x3FF) + 0xDC00))
        case 3:
          return fromCharCode(((0x0f & cccc.charCodeAt(0)) << 12) | ((0x3f & cccc.charCodeAt(1)) << 6) | (0x3f & cccc.charCodeAt(2)))
        default:
          return fromCharCode(((0x1f & cccc.charCodeAt(0)) << 6) | (0x3f & cccc.charCodeAt(1)))
      }
    }
    var btou = function (b) {
      return b.replace(reBtou, cbBtou)
    }
    var cbDecode = function (cccc) {
      var len = cccc.length
      var padlen = len % 4
      var n = (len > 0 ? b64tab[cccc.charAt(0)] << 18 : 0) | (len > 1 ? b64tab[cccc.charAt(1)] << 12 : 0) | (len > 2 ? b64tab[cccc.charAt(2)] << 6 : 0) | (len > 3 ? b64tab[cccc.charAt(3)] : 0)
      var chars = [fromCharCode(n >>> 16), fromCharCode((n >>> 8) & 0xff), fromCharCode(n & 0xff)]
      chars.length -= [0, 0, 2, 1][padlen]
      return chars.join('')
    }
    var atob = function (a) {
      return a.replace(/[\s\S]{1,4}/g, cbDecode)
    }
    var _decode = function (a) {
      return btou(atob(a))
    }
    var decode = function (a) {
      return _decode(String(a).replace(/[-_]/g,
        function (m0) {
          return m0 === '-' ? '+' : '/'
        }).replace(/[^A-Za-z0-9\+\/]/g, ''))
    }
  
    var install = function (Vue, options) {
      Vue.filter('base64', {
        read: function (val) {
          return decode(val)
        },
        write: function (val, oldVal) {
          return encode(val)
        }
      })
      // Vue.filter('base64', function (val, method) {
      //   if (method === 'decode') {
      //     return decode(val)
      //   }
      //   if (method === 'encode') {
      //     return encode(val)
      //   }
      // })
    }
    Base64Filter.install = install
    return Base64Filter
  })()
  
  Filters.install = function (Vue, options) {
    Vue.use(Filters.Base64Filter)
  }
  export default Filters
  export {encode}
  