title: I want to make a custom array in JS
body: <p>recently I decided to make my own website and for make it, I have to build a specific array who takes objects groups.
  Example :</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var my_array = [
    {y: '2015', a: 84},
    {y: '2016', a: 46},
    {y: '2017', a: 74},
    {y: '2018', a: 13},
    {y: '2019', a: 35},
    {y: '2020', a: 56}
  ]</code></pre>
  </div>
  </div>
  </p>
  <p>And I have to build it inside a loop, my problem is when I modify y whith my_array.y = '2021',that modify all y elements, but I want modify just one element.</p>