fairnesscoop / permacoop

export class ArrayUtils {

  public static range(start: number, end: number, step: number = 1) {

    function* generateRange() {

      let x = start - step;

      while (x <= end - step) {

        yield (x += step);

      }

    }

    return {

      [Symbol.iterator]: generateRange

    };

  }

  public static flatMap<T, V>(items: T[], fn: (x: T) => V[]): V[] {

    const arr = [];

    for (let item of items) {

      arr.push(...fn(item));

    }

    return arr;

  }

}