Benchmark: Array concat vs spread vs push spread, loop, apply, assign

Script Preparation code:

var subarrs = [
 [ "hello", true, 7 ],
 [ "yes", "no", "maybe", false, 27 ],
 [ 16, "I", "wonder", "what", "will", "be", "fastest"]
];

Tests:

Array.prototype.concat
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other = other.concat(subarrs[i]); }
spread operator
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other = [ ...other, ...subarrs[i] ] }
Push Spread
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other.push(...subarrs[i]); }
Push Apply
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other.push.apply(other, subarrs[i]); }
Push Loop
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ for (var jarr = subarrs[i], jen = jarr.length, j = 0; j < jen; j++){ other.push(jarr[j]); } }
Assign length loop
var other = [1, 2, 3]; for (var i = 0, j, m, a, n = subarrs.length; i < n; ++i) for (j = 0, a = subarrs[i], m = a.length; j < m; ++j) other[other.length] = a[j];
minified assign loop
for(var r,s,a,e=[1,2,3],g=0,h=subarrs.length;g<h;++g)for(r=0,s=(a=subarrs[g]).length;r<s;++r)e[e.length]=a[r];

Historical Performance Data aggregated from 9 community runs

Desktop Results:

Chrome 9 runs

Assign length loop

6.5M/s

Push Loop

5.7M/s

minified assign loop

5.6M/s

Push Spread

5.1M/s

Push Apply

5.0M/s

spread operator

4.6M/s

Array.prototype.concat

2.5M/s

Fastest: Assign length loop (2.6x faster)

View exact numbers

✓ Assign length loop: 6,505,694 ops/sec
• Push Loop: 5,717,669 ops/sec
• minified assign loop: 5,638,868 ops/sec
• Push Spread: 5,107,066 ops/sec
• Push Apply: 5,048,884 ops/sec
• spread operator: 4,560,771 ops/sec
• Array.prototype.concat: 2,464,892 ops/sec

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator
Push Spread
Push Apply
Push Loop
Assign length loop
minified assign loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Mac OS X 10.15.7

View result in a separate tab

Push Loop

24.3M/s

minified assign loop

22.7M/s

Assign length loop

22.7M/s

Push Spread

16.7M/s

Push Apply

16.4M/s

spread operator

10.3M/s

Array.prototype.concat

4.5M/s

View exact numbers

Test name	Executions per second
✓ Push Loop	24,262,436 Ops/sec
minified assign loop	22,748,166 Ops/sec
Assign length loop	22,736,912 Ops/sec
Push Spread	16,740,816 Ops/sec
Push Apply	16,423,918 Ops/sec
spread operator	10,300,961 Ops/sec
Array.prototype.concat	4,461,666 Ops/sec

Array concat vs spread vs push spread, loop, apply, assign (version: 4)

Compare the new ES6 spread operator with the traditional concat() method and push

Comparing performance of: `Array.prototype.concat vs spread operator vs Push Spread vs Push Apply vs Push Loop vs Assign length loop vs minified assign loop`

Created: 5 years ago by: Registered User

Go to the latest result

Array.prototype.concat

spread operator

Push Spread

Push Apply

Push Loop

Assign length loop

minified assign loop

Historical Performance Data aggregated from 9 community runs

Desktop Results:

Chrome 9 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Array concat vs spread vs push spread, loop, apply, assign (version: 4)

Compare the new ES6 spread operator with the traditional concat() method and push

Comparing performance of: Array.prototype.concat vs spread operator vs Push Spread vs Push Apply vs Push Loop vs Assign length loop vs minified assign loop

Created: 5 years ago by: Registered User

Go to the latest result

Array.prototype.concat

spread operator

Push Spread

Push Apply

Push Loop

Assign length loop

minified assign loop

Historical Performance Data aggregated from 9 community runs

Desktop Results:

Chrome 9 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `Array.prototype.concat vs spread operator vs Push Spread vs Push Apply vs Push Loop vs Assign length loop vs minified assign loop`