title: How to change a property on an object without mutating it?
body: <pre><code>const a = {x: &quot;Hi&quot;, y: &quot;Test&quot;}
  const b = ???
  // b = {x: &quot;Bye&quot;, y: &quot;Test&quot;}
  // a = {x: &quot;Hi&quot;, y: &quot;Test&quot;}
  </code></pre>
  <p>How can I set <code>b.x</code> to <code>&quot;Bye&quot;</code> without mutating a?</p>