title: how to push an element at index 0 of an array
body: <p>i have a situation like this,</p>
  
  <p>i have 2 <code>array1</code>  as <code>array1 = ["fruit","vegetables"];</code></p>
  
  <p>and </p>
  
  <p><code>array2 = [["apple","banana"],["tomato"]];  // index 0:represent fruit i,e (["apple","banana"]), index 1: vegetables i,e (["tomato"])</code></p>
  
  <p><strong>my question</strong> :  how can i <code>push item</code> from <code>array1</code>  so as to make my <code>array2</code> look like this </p>
  
  <p><code>[["fruit","apple","banana"],["vegetables","tomato"]];</code></p>
  
  <p>with that i can determine <code>index:0</code> as <code>category</code>.</p>
  
  <p><strong>MY</strong> <code>data structure</code> is  these 2 <code>array</code> <code>array1 = ["fruit","vegetables"];</code>  AND   <code>array2 = [["apple","banana"],["tomato"]];</code>  </p>
  
  <p>if i'm able to get <code>key</code> <code>value</code> pair <code>array</code> that would good for me.</p>
  
  <p>my sample data:</p>
  
  <pre><code>array1 = ["fruit","vegetables"];
  
  
  array2 = [["apple","banana"],["tomato"]]; //expected output :[["fruit","apple","banana"],["vegetables","tomato"]];
  </code></pre>