Benchmark: Reassignment of Var vs Const vs Let

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Tests:

Var
function foo() { var x = { value: 10 } x = { value: 11 } }
Const
function foo() { const x = { value: 10 } x.value = 11 }
Let
function foo() { let x = { value: 10 } x = { value: 11 } }
Const from inline function
function foo() { const bar = () => { const x = {value: 11} } const y = bar() }

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 runs

Let

264.1M/s

Const from inline function

263.4M/s

Const

258.3M/s

Var

255.4M/s

View exact numbers

✓ Let: 264,074,208 ops/sec
• Const from inline function: 263,389,600 ops/sec
• Const: 258,326,288 ops/sec
• Var: 255,446,048 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
Var
Const
Let
Const from inline function

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/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Mac OS X 10.15.7

View result in a separate tab

Var

284.7M/s

Let

261.7M/s

Const from inline function

259.9M/s

Const

249.6M/s

View exact numbers

Test name	Executions per second
✓ Var	284,707,168 Ops/sec
Let	261,721,552 Ops/sec
Const from inline function	259,947,328 Ops/sec
Const	249,601,200 Ops/sec

Reassignment of Var vs Const vs Let (version: 2)

Comparing performance of: `Var vs Const vs Let vs Const from inline function`

Created: one year ago by: Registered User

Go to the latest result

Var

Const

Let

Const from inline function

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Reassignment of Var vs Const vs Let (version: 2)

Comparing performance of: Var vs Const vs Let vs Const from inline function

Created: one year ago by: Registered User

Go to the latest result

Var

Const

Let

Const from inline function

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `Var vs Const vs Let vs Const from inline function`