Flatten a config

A config file can hold objects inside objects. Write flattenObject(object). It returns a new object that has no nested objects. Each key of the result is the path of keys to a value, joined with dots.

For example, { server: { port: 80, tls: { on: true } }, name: "web" } becomes { "server.port": 80, "server.tls.on": true, "name": "web" }.

• Only a plain object that has at least one key is opened. All other values stay as they are: numbers, strings, booleans, null and arrays. Do not look inside arrays.
• An empty object is a value too. { a: {} } becomes { "a": {} }.
• A key never holds a dot, and no two paths are the same.

Examples

Call	Result
flattenObject({ server: { port: 80, tls: { on: true } }, name: 'web' })	{ 'server.port': 80, 'server.tls.on': true, name: 'web' }
flattenObject({ a: 1 })	{ a: 1 }
flattenObject({})	{}