Function arrayGetOrExtendWith

arrayGetOrExtendWith<T extends object>(
    arr: T[],
    index: number,
    f: (index: number) => T,
): T
Gets the element at the given index, extending via a factory function if out of bounds.
Type Parameters
- T extends object
  Element type.
Parameters
- arr: T[]
  The dense array.
- index: number
  Integer array index from 0 through 2 ** 32 - 2.
- f: (index: number) => T
  Factory called with each new index to create an entry.
Returns T
The element at index.
Throws
If index is not a valid array index.

Remarks
The factory is not called for an existing entry. Unlike arrayGetOrExtend, this accepts entries of any object type, including built-ins and class instances.
Example
```
const dates: Date[] = [];
arrayGetOrExtendWith(dates, 1, (i) => new Date(i)); // Date at timestamp 1
```
- Defined in data-structure/array.ts:107