title: How do I generate a new JavaScript array given the indexes and values in two other arrays?
body: <p>I have two arrays, <code>arr1 = [1,2,7,9,10]</code> and <code>arr2 = [40,50,70,80,30]</code>. From these two arrays, I have a zero-filled array of length 15 that I want to populate using <code>arr1</code> as the indexes and <code>arr2</code> as the values: <code>[0,40,50,0,0,0,0,70,0,80,30,0,0,0,0]</code></p>
  
  <p>What is the code to do this?</p>