This is a script I had an inspiration to write that contains a deep copy function structure. Since the .slice() method and the spread operator copy only the first level, they are effective with reference types that contain only primitive values. This is an attempt to solve that (I realize I could acheive this with JSON.parse(JSON.stringify(object)) but decided to strike out on my own and get some practice 😁). One obvious limitation in this appraoch is call stack capacity (since I am using recursion), but for sufficiently non-complex reference structures (e.g. a trivial amount of nested arrays/objects), which should be the majority, this should be a good solution.

const original = [[{ obj: { id: 1 } }], 2, 3];
const copy = makeCopy(original);

copy[0][0].obj.id = 2; // modify copy

console.log(copy[0][0].obj.id); // logs 2
console.log(original[0][0].obj.id); // logs 1