Challenge 1 — Solution

Task: Create const original = [1, 2, 3]. Create const sameRef =
original (no copy) and const shallowCopy = [...original]. Push 4
onto sameRef and 5 onto shallowCopy, then log original, sameRef, and
shallowCopy to show the different effects.

const original = [1, 2, 3];
const sameRef = original;
const shallowCopy = [...original];

sameRef.push(4);
shallowCopy.push(5);

console.log(original);
console.log(sameRef);
console.log(shallowCopy);


Expected output:

[1, 2, 3, 4]
[1, 2, 3, 4]
[1, 2, 3, 5]


Notes:
- sameRef.push(4) changed original too, since sameRef and original
  are literally the same array in memory — there was never a copy
  made at all, just a second name for the same data.
- shallowCopy.push(5) only affected shallowCopy, since [...original]
  created a genuinely separate array — for an array of plain numbers
  (primitives), a shallow copy is already a fully independent copy.
- original never received the 5, confirming shallowCopy really is
  independent, unlike sameRef.