title: JavaScript (ES6): Named parameters and default values
body: <p>Coming from Python and really liking the way to set named parameters and default values - now it seems that ES6 allows me to do similar. But I can't see why this last call breaks:</p>
  
  <pre><code>fun = ({first=1, last=1}) =&gt; (1*first+2*last)
  
  console.log("-----------")
  
  console.log( fun({first:1, last:2}) )
  
  console.log("-----------")
  
  console.log( fun({last:1, first:2}) )
  
  console.log("-----------")
  
  console.log( fun() ) // Breaks
  </code></pre>