title: Javascript function with no arguments and changing return values
body: <p>I'm looking to write a function in Javascript that will take no arguments, but produce a different (predictable) output each time. I'll be using it for testing, so I need to be sure that I can predict the outputs, meaning that using <code>Date.now()</code> will not work. I'm thinking about using a seeded RNG (or PRNG), but I'm wondering if there are any alternate solutions.</p>
  
  <p>Edit: the function must be self contained, no variables or data outside the scope of the function.</p>