title: What is the best way in JavaScript to trim down the properties of an object?
body: <p>Situation: </p>
  
  <p>I have an object like </p>
  
  <pre><code>{ prop_1 : val_1, prop_2 : val_2, prop_3 : val_3 , ..., prop_N : val_N } 
  </code></pre>
  
  <p>and I want to remove all properties that aren't <code>prop_i</code>, <code>prop_j</code> or <code>prop_K</code> ?</p>
  
  <p>What is the best way to do this other than the "brute force" way of </p>
  
  <pre><code>var original = { prop_1 : val_1, prop_2 : val_2, prop_3 : val_3 , ..., prop_N : val_N };
  var newguy = { prop_i : original.prop_i, prop_j : original.prop_j, prop_k : original.prop_k };
  original = newguy;
  </code></pre>
  
  <p>????</p>