title: Modifying a copy of a JavaScript object is causing the original object to change
body: <p>I am copying <code>objA</code> to <code>objB</code></p>
  <pre><code>const objA = { prop: 1 }, 
  const objB = objA; 
  objB.prop = 2;
  console.log(objA.prop); // logs 2 instead of 1
  </code></pre>
  <p>same problem for Arrays</p>
  <pre><code>const arrA = [1, 2, 3], 
  const arrB = arrA; 
  arrB.push(4); 
  console.log(arrA.length); // `arrA` has 4 elements instead of 3.
  </code></pre>