import { fromUndefinedable } from './Option';
import { pipe } from './function';

export const map = <A, B>(f: (a: A) => B) => (arr: Array<A>) => arr.map(f);

export const filter = <A>(f: (a: A) => boolean) => (arr: Array<A>) =>
  arr.filter(f);

export const reject = <A>(f: (a: A) => boolean) => (arr: Array<A>) =>
  arr.filter(a => !f(a));

export const find = <A>(f: (a: A) => boolean) => (arr: Array<A>) =>
  pipe(arr, array => array.find(f), fromUndefinedable);

export const reduce = <A, B>(
  reduceFn: (acc: B, cur: A, index: number) => B,
  init: B
) => (arr: Array<A>) => arr.reduce(reduceFn, init);

export const flat = <A>(arr: Array<Array<A>>) =>
  reduce((acc: Array<A>, current: Array<A>) => [...acc, ...current], [])(arr);