Function makeBy

packages/effect/src/Iterable.ts:37–54

(f: (i: number) => A, options?: {
  readonly length?: number
})

 * @since 2.0.0
 */
export const makeBy = <A>(f: (i: number) => A, options?: {
  readonly length?: number
}): Iterable<A> => {
  const max = options?.length !== undefined ? Math.max(1, Math.floor(options.length)) : Infinity
  return {
    [Symbol.iterator]() {
      let i = 0
      return {
        next(): IteratorResult<A> {
          if (i < max) {
            return { value: f(i++), done: false }
          }
          return { done: true, value: undefined }
        }
      }
    }
  }
}

/**
 * Return a `Iterable` containing a range of integers, including both endpoints.