// Unique ID creation requires a high quality random # generator. In the // browser this is a little complicated due to unknown quality of Math.random() // and inconsistent support for the `crypto` API. We do the best we can via // feature-detection

// getRandomValues needs to be invoked in a context where “this” is a Crypto // implementation. Also, find the complete implementation of crypto on IE11. var getRandomValues = (typeof(crypto) != 'undefined' && crypto.getRandomValues && crypto.getRandomValues.bind(crypto)) ||

(typeof(msCrypto) != 'undefined' && typeof window.msCrypto.getRandomValues == 'function' && msCrypto.getRandomValues.bind(msCrypto));

if (getRandomValues) {

// WHATWG crypto RNG - http://wiki.whatwg.org/wiki/Crypto
var rnds8 = new Uint8Array(16); // eslint-disable-line no-undef

module.exports = function whatwgRNG() {
  getRandomValues(rnds8);
  return rnds8;
};

} else {

// Math.random()-based (RNG)
//
// If all else fails, use Math.random().  It's fast, but is of unspecified
// quality.
var rnds = new Array(16);

module.exports = function mathRNG() {
  for (var i = 0, r; i < 16; i++) {
    if ((i & 0x03) === 0) r = Math.random() * 0x100000000;
    rnds[i] = r >>> ((i & 0x03) << 3) & 0xff;
  }

  return rnds;
};

}