npm and error messages

node_modules/randombytes/browser.js

@@ -0,0 +1,38 @@
+'use strict'
+
+function oldBrowser () {
+  throw new Error('Secure random number generation is not supported by this browser.\nUse Chrome, Firefox or Internet Explorer 11')
+}
+
+var Buffer = require('safe-buffer').Buffer
+var crypto = global.crypto || global.msCrypto
+
+if (crypto && crypto.getRandomValues) {
+  module.exports = randomBytes
+} else {
+  module.exports = oldBrowser
+}
+
+function 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
+    crypto.getRandomValues(rawBytes)
+  }
+
+  // XXX: phantomjs doesn't like a buffer being passed here
+  var bytes = Buffer.from(rawBytes.buffer)
+
+  if (typeof cb === 'function') {
+    return process.nextTick(function () {
+      cb(null, bytes)
+    })
+  }
+
+  return bytes
+}