Unsquash Object

Requirements

• Export unsquashObject as named and default. Reconstruct a new nested plain object from own enumerable dot-delimited keys.
• Every path segment is a non-empty string. Numeric segments remain object keys; do not create arrays automatically.
• Shared prefixes must share a single nested object. Inputs do not contain conflicting paths such as a and a.b.
• Preserve leaf values by reference and do not mutate the input. Empty input returns {}.
• Safely create own properties for __proto__, constructor, and prototype without modifying any prototypes. Cycles, conflicting paths, and malformed paths are outside the contract.

Examples

Input: unsquashObject({ "user.name": "Ada", "user.settings.theme": "dark" });
Output: { user: { name: "Ada", settings: { theme: "dark" } } }