34. Deep Clone

Implement deepClone for values composed of primitives, arrays, and plain objects.

1) Supported input scope

• Primitive values (number, string, boolean, null, undefined)
• Arrays (possibly nested)
• Plain objects (possibly nested)

2) Clone behavior

• Return a structurally equal deep copy.
• Nested objects/arrays must not share references with the original.
• Modifying the clone must not mutate original nested values.

3) Edge cases

• Empty objects/arrays should clone correctly.
• Primitive input should be returned as-is.

4) Assumption (base version)

• You may assume input does not contain circular references.
• Special objects (Map/Set/Date/RegExp) are out of scope in this base problem.

Examples

const original = { a: 1, b: { c: 2 } }
const cloned = deepClone(original)
cloned.b.c = 99

// original.b.c is still 2

const arr = [1, [2, 3], { x: 4 }]
const cloned = deepClone(arr)
cloned[1][0] = 9

// arr[1][0] is still 2