Benchmark: Compare Array.splice() and Array.copyWithin() to move item within an array

Script Preparation code:

var data = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99]

function moveItemBySplice(from, to) {
  // remove `from` item and store it
  var f = data.splice(from, 1)[0];
  // insert stored item into position `to`
  data.splice(to, 0, f);
}

function moveItemByCopyWithin(from, to) {
  const f = data[from];
  if (to > from) {
    // copy items after `from` until `to` one index to the left
    data.copyWithin(from, from + 1, to + 1);
  } else {
    // copy items from `to` until before `from` one index to the right
    data.copyWithin(to + 1, to, from);
  }
  // insert stored item into position `to`
  data[to] = f;
}

Tests:

Move element by Array.splice()
moveItemBySplice(3, 40); moveItemBySplice(50, 10); moveItemBySplice(45, 96); moveItemBySplice(7, 15);
Move element by Array.copyWithin()
moveItemByCopyWithin(3, 40); moveItemByCopyWithin(50, 10); moveItemByCopyWithin(45, 96); moveItemByCopyWithin(7, 15);

Historical Performance Data aggregated from 15 community runs

Desktop Results:

Chrome 10 runs

Move element by Array.splice()

2.2M/s

Move element by Array.copyWithin()

228K/s

Fastest: Move element by Array.splice() (9.9x faster)

View exact numbers

✓ Move element by Array.splice(): 2,244,862 ops/sec
• Move element by Array.copyWithin(): 227,825 ops/sec

Firefox 5 runs

Move element by Array.copyWithin()

3.3M/s

Move element by Array.splice()

1.6M/s

Fastest: Move element by Array.copyWithin() (2.0x faster)

View exact numbers

✓ Move element by Array.copyWithin(): 3,308,300 ops/sec
• Move element by Array.splice(): 1,641,769 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Test case name	Result
Move element by Array.splice()
Move element by Array.copyWithin()

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36 Edg/148.0.0.0

Browser/OS: Chrome 148 on Windows

View result in a separate tab

Move element by Array.splice()

2.2M/s

Move element by Array.copyWithin()

242K/s

View exact numbers

Test name	Executions per second
✓ Move element by Array.splice()	2,164,525 Ops/sec
Move element by Array.copyWithin()	241,711 Ops/sec

Compare Array.splice() and Array.copyWithin() to move item within an array (version: 1)

Comparing performance of: `Move element by Array.splice() vs Move element by Array.copyWithin()`

Created: one year ago by: Guest

Go to the latest result

Move element by Array.splice()

Move element by Array.copyWithin()

Historical Performance Data aggregated from 15 community runs

Desktop Results:

Chrome 10 runs

Firefox 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Compare Array.splice() and Array.copyWithin() to move item within an array (version: 1)

Comparing performance of: Move element by Array.splice() vs Move element by Array.copyWithin()

Created: one year ago by: Guest

Go to the latest result

Move element by Array.splice()

Move element by Array.copyWithin()

Historical Performance Data aggregated from 15 community runs

Desktop Results:

Chrome 10 runs

Firefox 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `Move element by Array.splice() vs Move element by Array.copyWithin()`