Ractive.js get checked values checkbox into array

I am trying to get values of checked in checkboxes and store in an array.Whenever any checkbox is clicked by user, I want to update the array with values of only checked checkboxes.How can I do?

<label>
  <input type='checkbox'>
  {{#if checked}}checked!{{else}}Circle{{/if}}
</label><br>
<label>
  <input type='checkbox'>
  {{#if checked}}checked!{{else}}Star{{/if}}
</label><br>
<label>
  <input type='checkbox'>
  {{#if checked}}checked!{{else}}Square{{/if}}
</label><br>
<label>
  <input type='checkbox'>
  {{#if checked}}checked!{{else}}Hexagon{{/if}}
</label><br>
<label>
  <input type='checkbox'>
  {{#if checked}}checked!{{else}}Triangle{{/if}}
</label><br>
<label>
  <input type='checkbox'>
  {{#if checked}}checked!{{else}}Polygon{{/if}}
</label>