Function flattenObject

flattenObject<T extends object>(
    values: T,
    flattenPredicate?: (obj: any) => any,
    separator?: string,
    keyPrefix?: string,
): T
Flatten an object with nested objects to a flat structure in which nested objects can be accessed directly using a key separator. I.e:
```
flattenNestedObject({ foo: { bar: 'test' } }); // { 'foo.bar': 'test' }
```
Creates a new object and does not alter the existing structure
Type Parameters
- T extends object
Parameters
- values: T
  Object to flatten
- OptionalflattenPredicate: (obj: any) => any
  when this predicate returns false the object will not be flattened otherwise; if not set all objects will be flattened
- separator: string = '.'
  optional separator
- OptionalkeyPrefix: string
  key which will prefixes the new keys
Returns T
- Defined in packages/util/src/object.ts:273