export const range = (start, end) => {
  const result = [];

  for (let i = start; i < end; i++) {
    result.push(i);
  }

  return result;
};

export const flatten = lists => lists.reduce((x, y) => x.concat(y), []);

export const from = list => {
  if (!list.length) {
    return [];
  }

  const result = [];

  for (let i = 0; i < list.length; i++) {
    result.push(list[i]);
  }

  return result;
};

export const findIndexes = (l, key) => l.reduce((a, e, i) => {
  if (e[key]) {
    a.push(i);
  }

  return a;
}, []);