bifurcate

Splits values into two groups, based on the result of the given filter array.

• Use Array.prototype.reduce() and Array.prototype.push() to add elements to groups, based on filter.
• If filter has a truthy value for any element, add it to the first group, otherwise add it to the second group.

const bifurcate = (arr, filter) =>
  arr.reduce((acc, val, i) => (acc[filter[i] ? 0 : 1].push(val), acc), [
    [],
    [],
  ]);

bifurcate(['beep', 'boop', 'foo', 'bar'], [true, true, false, true]);
// [ ['beep', 'boop', 'bar'], ['foo'] ]