import { identity } from "@sanjo/identity"

export function getExtrema<T>(
  array: T[],
  getter: (value: T) => any = identity,
  isMoreExtreme: (a: any, b: any) => boolean,
): T | null {
  if (array.length === 0) {
    return null
  }

  let extremeIndex = 0
  let extremeValue = getter(array[0])
  for (let index = 1; index < array.length; index++) {
    const value = getter(array[index])
    if (isMoreExtreme(value, extremeValue)) {
      extremeIndex = index
      extremeValue = value
    }
  }

  return array[extremeIndex]
}