Run results for: JS Performance (const vs let vs var)

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36

Browser: Chrome 109

Operating system: Windows

Device Platform: Desktop

Date tested: 3 months ago

Script Preparation code:

const maxObjectSize = 10
const maxRuns = 1000000;

Tests:

CONST <> CONSTRUCTION
for (let i = 0; i < maxRuns; i++) { const x = i; }
CONST <> UPDATE
const x = {v: 0} for (let i = 0; i < maxRuns; i++) { x.v = 1; }
CONST <> DELETE
const x = {} for (let i = 0; i < maxObjectSize; i++) { x[`key_{i}`] = 1 } for (let i = 0; i < maxObjectSize; i++) { delete x[`key_{i}`] }
CONST <> ACCESS
const x = {} for (let i = 0; i < maxObjectSize; i++) { x[`key_{i}`] = 1 } for (let i = 0; i < maxObjectSize; i++) { console.log(x[`key_{i}`]); }
LET <> CONSTRUCTION
for (let i = 0; i < maxRuns; i++) { let x = i; }
LET <> UPDATE
let x = {v: 0} for (let i = 0; i < maxRuns; i++) { x.v = 1; }
LET <> DELETE
let x = {} for (let i = 0; i < maxObjectSize; i++) { x[`key_{i}`] = 1 } for (let i = 0; i < maxObjectSize; i++) { delete x[`key_{i}`] }
LET <> ACCESS
let x = {} for (let i = 0; i < maxObjectSize; i++) { x[`key_{i}`] = 1 } for (let i = 0; i < maxObjectSize; i++) { console.log(x[`key_{i}`]); }
VAR <> ASSIGNMENT
for (let i = 0; i < maxRuns; i++) { var x = i; }
VAR <> UPDATE
var x = {v: 0} for (let i = 0; i < maxRuns; i++) { x.v = 1; }
VAR <> ACCESS
var x = {} for (let i = 0; i < maxObjectSize; i++) { x[`key_{i}`] = 1 } for (let i = 0; i < maxObjectSize; i++) { console.log(x[`key_{i}`]); }
VAR <> DELETE
var x = {} for (let i = 0; i < maxObjectSize; i++) { x[`key_{i}`] = 1 } for (let i = 0; i < maxObjectSize; i++) { delete x[`key_{i}`] }