title: push array into an array object without property declared
body: <pre><code>parent = {[
  "item":""
  ]}
  
  child = [1,2,3]
  </code></pre>
  
  <p>to push my child into parent I can do </p>
  
  <pre><code>$.each(function(){
  this.item = child;
  }
  </code></pre>
  
  <p>but how to push the child into the item property if I don't have the item property declare the parent? It's quite redundant to have the item equal to empty string. </p>