title: How to add element to JSON object with Javascript
body: <p>So say I have a JSON object like this: <br></p>
  
  <pre><code>{"name":"asdf","quantity":"3","_id":"v4njTN7V2X10FbRI"}
  </code></pre>
  
  <p>And I can't modify it when it is created. But I want to make it look like this:<br></p>
  
  <pre><code>{"name":"asdf","quantity":"3","_id":"v4njTN7V2X10FbRI", checked: true}
  </code></pre>
  
  <p>So how would I do that with javascript?</p>