Function scan

scan<TElement, TAccumulate = TElement>(
    source: Iterable<TElement>,
    accumulator: Accumulator<TElement, TAccumulate>,
    seed?: TAccumulate,
): IEnumerable<TAccumulate>
Accumulates the sequence and emits each intermediate result.
Type Parameters
- TElement
  Type of elements within the source iterable.
- TAccumulate = TElement
  Accumulator type produced by accumulator; defaults to TElement when seed is omitted.
Parameters
- source: Iterable<TElement>
  The source iterable.
- accumulator: Accumulator<TElement, TAccumulate>
  Function that merges the current accumulator value with the next element to produce the subsequent accumulator.
- Optionalseed: TAccumulate
  Optional initial accumulator. When omitted, the first element supplies the initial accumulator and is emitted as the first result.
Returns IEnumerable<TAccumulate>
A deferred sequence containing every intermediate accumulator produced by accumulator.
Throws
Thrown when source is empty and seed is not provided.

Remarks
source is enumerated exactly once. Supplying seed prevents exceptions on empty sources but the seed itself is not emitted.
Example
```
const numbers = [1, 2, 3, 4, 5];
const runningTotal = scan(numbers, (acc, x) => acc + x).toArray();
console.log(runningTotal); // [1, 3, 6, 10, 15]
```
- Defined in src/enumerator/functions/scan.ts:22