randombytes.js

const getRandomValues = byteArray => {
  for (let i = 0; i < byteArray.length; i++) {
    byteArray[i] = Math.floor(256 * Math.random());
  }
};
const randomBytes = (size, cb) => {
  // phantomjs needs to throw
  if (size > 65536) throw new Error("requested too many random bytes");
  // in case browserify  isn't using the Uint8Array version
  var rawBytes = new global.Uint8Array(size);

  // This will not work in older browsers.
  // See https://developer.mozilla.org/en-US/docs/Web/API/window.crypto.getRandomValues
  if (size > 0) {
    // getRandomValues fails on IE if size == 0
    getRandomValues(rawBytes);
  }
  // XXX: phantomjs doesn't like a buffer being passed here
  var bytes = Buffer.from(rawBytes.buffer);

  if (cb) {
    cb(bytes);
  }
  return bytes;
};

// these 2 lines are simply to make brorand work (used by eth-lightwallet)
global.self = global;
global.self.crypto = { getRandomValues };

const crypto = require("crypto");
window.crypto = crypto;
global.self.crypto = crypto;

module.exports = randomBytes;