Function findIndex

findIndex<T>(
pred: (value: T) => boolean,
): (list: List.List<T>) => Option.Option<number>
Finds the position of element which satisfies pred in the list. If the list is infinite and the element is not found, this will hang forever.
Type Parameters
- T
Parameters
- pred: (value: T) => boolean
  The match condition of element to find.
Returns (list: List.List<T>) => Option.Option<number>
The found position if exists.

Examples
Example
```
const list = fromArray([1, 4, 2, 3, 5]);

expect(findIndex((x: number) => 4 <= x)(list)).toStrictEqual(Option.some(1));
expect(findIndex((x: number) => 0 <= x)(list)).toStrictEqual(Option.some(0));
expect(findIndex((x: number) => 8 <= x)(list)).toStrictEqual(Option.none());
```
- Defined in src/list.ts:1720