Run results for: Sorting array into 2 arrays with reduce vs forEach

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36

Browser: Chrome 85

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
reduce	106185.3 Ops/sec
forEach	90362.0 Ops/sec

Script Preparation code:

var timeSlots = [
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 1},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 0},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 1},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 0},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 1},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 0},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 1},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 0},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 1},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 0},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 1},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 0},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 1},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 0},
  {start_date: "2020-10-15T19:14:46.599Z", end_date: "2020-10-15T19:14:46.599Z", id: 1},
];

Tests:

reduce
var [ newTimeSlots, editedTimeSlots ] = timeSlots.reduce( (splitSlots, slot ) => { var arrayIndex = slot.id > 0 ? 1 : 0; splitSlots[arrayIndex].push({...slot, meeting: 1}); return splitSlots; }, [[], []]);
forEach
var newTimeSlots = []; var editedTimeSlots = []; timeSlots.forEach(slot => { slot.id > 0 ? editedTimeSlots.push({...slot, meeting: 1}) : newTimeSlots.push({...slot, meeting: 1}); });

Run results for: Sorting array into 2 arrays with reduce vs forEach

When sorting an array, you can use reduce or forEach

reduce

forEach