Run results for: Reassignment of Var vs Const vs Let

Run details:

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: Chrome 137

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Let

255.9M/s

Var

252.6M/s

Const

246.7M/s

View exact numbers

Test name	Executions per second
✓ Let	255,905,808 Ops/sec
Var	252,649,152 Ops/sec
Const	246,666,976 Ops/sec

HTML Preparation code:

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Script Preparation code:

/*your preparation JavaScript code goes here
To execute async code during the script preparation, wrap it as function globalMeasureThatScriptPrepareFunction, example:*/
async function globalMeasureThatScriptPrepareFunction() {
    // This function is optional, feel free to remove it.
    // await someThing();
}

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() }

Run results for: Reassignment of Var vs Const vs Let

Var

Const

Let

Const from inline function