title: How to add a new item to struct in JavaScript?
body: <p>I have a struct in JavaScript</p>
  
  <pre><code>    settings = {
          "type-1": {
              "setting-1": true,
              "setting-2": 2
           }
          "type-2": {
              "setting-3": "value",
           }
      };
  </code></pre>
  
  <p>I can modify the items:</p>
  
  <pre><code>settings["type-1"]["setting-1"] = false;
  </code></pre>
  
  <p>But how can I add a new item in this struct?</p>
  
  <p>Trying</p>
  
  <pre><code>settings["type-new"]["setting-100"] = "new one";
  </code></pre>
  
  <p>But settings["type-new"] is undefined. So how to add a new one?</p>