Flatten Deep Object

Write a function flattenObject that takes a deeply nested JavaScript object and returns a new object where nested keys are represented in dot notation.

Input:

• A nested object with keys and values of any depth

Output:

• A new object where each key is a dot-separated path to the corresponding value

Example Inputs & Outputs

// Example 1:
Input: { a: { b: 1 } }
Output: { "a.b": 1 }

// Example 2:
Input: { a: { b: { c: 2 }, d: 3 } }
Output: { "a.b.c": 2, "a.d": 3 }

// Example 3:
Input: { x: 1, y: { z: { k: 5 } } }
Output: { "x": 1, "y.z.k": 5 }

// Example 4:
Input: {}
Output: {}

// Example 5:
Input: { a: null, b: { c: undefined } }
Output: { "a": null, "b.c": undefined }

Constraints & Edge Cases

• Keys are always strings
• Values may be any primitive or object
• Object may be empty
• Values like null, undefined, or falsy primitives should be preserved
• Does not mutate the original object