binary.js

var binary = {
  
  number_to_string: function(v) {
    var r = "";
    while ( v >= 2 ) {
      var m = v % 2;
      r = m + r;
      if (m === 1)
        v = (v - 1) / 2;
      else
        v = v / 2;
    }
    return v + r;
  },

  string_to_number: function(v) {
    var r = 0;
    var b = 1;
    var m = v.length - 1;
    for(var n = 0; n <= m; ++n) {
      r = r + v[m - n] * b;
      b = b * 2;
    }
    return r;
  },
  
};

var x = 4;

var c = binary.number_to_string(x);
console.log(c);

var s = binary.string_to_number(c);
console.log(s);