title: Move key in object of object up (swap indexes)
body: <p>I'm working with an object of objects. I need to keep it as an object because I'm work with an API that requires me to keep it that way (that part is not debatable).</p>
  
  <p>This is an example schema of my object:</p>
  
  <pre><code>const obj = {
    1: { name: 'Initial Step 1', stepNumber: 1 },
    2: { name: 'Initial Step 2', stepNumber: 2 },
    3: { name: 'Initial Step 3', stepNumber: 3 },
  }
  </code></pre>
  
  <p>I need to implemented a <code>moveUp</code> function that will take the <code>stepNumber</code> and <code>obj</code> as the first and second parameters respectively.</p>
  
  <p>This <code>moveUp</code> function basically needs to swap one inner object with the object above it. Eg. <code>moveUp(2, obj)</code> should change the <code>obj</code> as follows:</p>
  
  <pre><code>{
    1: { name: 'Initial Step 2', stepNumber: 1 },
    2: { name: 'Initial Step 1', stepNumber: 2 },
    3: { name: 'Initial Step 3', stepNumber: 3 },
  }
  </code></pre>
  
  <p>The <code>stepNumber</code> will never be equal to <code>1</code>, thanks to the interface I've built.</p>
  
  <p>How should I implement my <code>moveUp</code> function?</p>
  
  <p>I basically need this:</p>
  
  <pre><code>export const moveUp = (stepNumber, obj) =&gt; {
      // I need help here
  };
  </code></pre>
  
  <p>Thanks!</p>