Function reduce

reduce<T>(
reducer: (accum: any, element: T, index: number, set: Set<T>) => any,
initial?: any,
): any
Create a new Set with elements that are filtered and transformed by a provided reducer function.
Type Parameters
- T
Parameters
- reducer: (accum: any, element: T, index: number, set: Set<T>) => any
  A reducer function applied to each value. Positional arguments are the accumulator, the value, the index of iteration, and the set being reduced.
- Optionalinitial: any
  The initial value of the returned accumulator.
Returns any
The final value of the accumulator.

See
Array#reduce