title: arrow functions: how to indicate un-needed parameters in destructuring
body: <p>Is there a way to indicate un-needed parameters in arrow function arguments (and during destructuring as well)?</p>
  
  <p>Contrived case in point where I am using <code>_</code> to indicate un-need parameters in my arrow function:</p>
  
  <pre><code>import _ from 'lodash';
  
  const m = [];
  m.push({k: 1, v: 'a'});
  m.push({k: 2, v: 'b'});
  m.push({k: 3, v: 'c'});
  
  const bExists = _.filter(m, ( {_,v}, _1, _2)=&gt;{
      return v==='b';
  }).length &gt; 0;
  </code></pre>
  
  <p>Two gripes with the above code:</p>
  
  <ol>
  <li><code>_</code> (used in languages like F#) is the same as the lodash import. Not a syntax error but still confusing</li>
  <li><p>subsequent <code>_</code> have to be renamed as <code>_1</code>, <code>_2</code> otherwise one gets: </p>
  
  <p>SyntaxError: es6/app.js: Argument name clash in strict mode </p></li>
  </ol>
  
  <p>I could simply omit the <code>_1</code> and <code>_2</code> arguments but only because in this particular example the unneeded ones appear at the end of the argument list.</p>
  
  <p>The first of the above gripes can obviously be solved by using some other name, yet the second one still stands (and whatever name is adopted as a convention would have to be mangled in subsequent unneeded arguments).</p>
  
  <p>So, is there language support to indicate unused parameters in arrow functions or (failing that) established conventions on that?</p>