title: push item to specific array object key
body: <p>how i can push a item on object expecific?<br />
  had follow structure :</p>
  <pre><code>//construction  
   const arrStr = ['a','b','c','d','e','f'];
   var finalObj = { };
   var objArray = {vhCal: [], vhRef: [], vhOcup: [], vhIlu: [], vhAcs: []};
   for(let x = 0; x &lt; arrStr.length ; x++ )
  {
      const val = arrStr[x];
      finalObj[val] = objArray;
  }
  </code></pre>
  <p><a href="https://i.stack.imgur.com/C4q6x.png" rel="nofollow noreferrer">structure</a>
  if i try to add a item to specific sub-object array, the item was added to all keys...</p>
  <pre><code>//assign
  finalObj[&quot;a&quot;].vhAcs.push('potato')
  // output :
  // a:
  // vhAcs: [&quot;potato&quot;]
  // vhCal: []
  // vhIlu: []
  // vhOcup: []
  // vhRef: []
  // b:
  // vhAcs: [&quot;potato&quot;]
  // vhCal: []
  // vhIlu: []
  // vhOcup: []
  // vhRef: []
  // c:
  // vhAcs: [&quot;potato&quot;]
  // vhCal: []
  // vhIlu: []
  // vhOcup: []
  // vhRef: []
  </code></pre>
  <p>only want add to 'a' key.</p>