@martintsan/brorand/index.js

Random number generator for browsers and node.js

var CryptoJS = require("crypto-js");
var r;

module.exports = function rand(len) {
  if (!r) r = new Rand(null);

  return r.generate(len);
};

function Rand(rand) {
  this.rand = rand;
}
module.exports.Rand = Rand;

Rand.prototype.generate = function generate(len) {
  return this._rand(len);
};

// Emulate crypto API using randy
// Rand.prototype._rand = function _rand(n) {
//   if (this.rand.getBytes)
//     return this.rand.getBytes(n);

//   var res = new Uint8Array(n);
//   for (var i = 0; i < res.length; i++)
//     res[i] = this.rand.getByte();
//   return res;
// };

Rand.prototype._rand = function _rand(n) {
  return CryptoJS.lib.WordArray.random(n).words;
};

if (typeof self === "object") {
  if (self.crypto && self.crypto.getRandomValues) {
    // Modern browsers
    Rand.prototype._rand = function _rand(n) {
      var arr = new Uint8Array(n);
      self.crypto.getRandomValues(arr);
      return arr;
    };
  } else if (self.msCrypto && self.msCrypto.getRandomValues) {
    // IE
    Rand.prototype._rand = function _rand(n) {
      var arr = new Uint8Array(n);
      self.msCrypto.getRandomValues(arr);
      return arr;
    };

    // Safari's WebWorkers do not have `crypto`
  } else if (typeof window === "object") {
    // Old junk
    Rand.prototype._rand = function () {
      throw new Error("Not implemented yet");
    };
  }
} else {
  // Node.js or Web worker with no crypto support
  try {
    var crypto = require("crypto");
    if (typeof crypto.randomBytes !== "function")
      throw new Error("Not supported");

    Rand.prototype._rand = function _rand(n) {
      return crypto.randomBytes(n);
    };
  } catch (e) {}
}