another bit compressor in pure javascript

anotherbitcompressor.js

// another bit compressor
// by stagas
// public domain

var bitEncode = function(bits) {
  var arr = []
  while (bits.length) {
    arr.push(String.fromCharCode(parseInt('1' + bits.substr(0, 15), 2)))
    bits = bits.substr(15)
  }
  return arr.join('')
}

var bitDecode = function(str) {
  var sarr = str.split('')
    , arr = []
    
  for (var i = 0, len=sarr.length, s; i<len; i++) {
    s = sarr[i].charCodeAt(0).toString(2)
    s = s.substr(s.indexOf(1) + 1)
    arr.push(s)
  }

  return arr.join('')
}

var bits =
  '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'
+ '110110010101010010101010010101111101010101011111010101001011101010011101010100101010110'

var compressed = bitEncode(bits)

console.log('Output:', compressed)

console.log('Down to', (compressed.length / bits.length * 100).toFixed(2), '% of original size')

console.log('Test:', bits == bitDecode(compressed))

gistfile2.txt

Output: ꪕ磌퓪쪶풯핟꩝Ꝕ햶ꪕꕽ꫺틪몥궲풪ꯪퟕ靓픪ꕒ▒뺩몝꥖ꪕ磌퓪쪶풯핟꩝Ꝕ햶ꪕꕽ꫺틪몥궲풪ꯪퟕ靓픪ꕒ▒뺩몝꥖ꪕ磌퓪ᥖ
Down to 6.69 % of original size