title: What does a variable directly followed by empty curly braces mean in Javascript?
body: <p>Going through the Eloquent Javascript book where I encountered something I haven't seen before.</p>
  
  <p>In the code snippet below the variable 'map' is followed by empty curly braces. Can someone please explain what this means? Does this do anything tot he function that follows.</p>
  
  <p>Also, can someone explain what map[event] = phi; does exactly? I take it this map refers to the variable 'map' we declared in the first line...</p>
  
  <pre><code>var map = {};
  function storePhi (event, phi) {
    map[event] = phi;
  }
  
  storePhi("pizza", 0.069);
  </code></pre>