Run results for: fromEntries vs for vs reduce

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:121.0) Gecko/20100101 Firefox/121.0

Browser: Firefox 121

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 2 years ago

for loop

11.4M/s

Object.fromPairs

2.5M/s

Array.reduce(...)

871K/s

View exact numbers

Test name	Executions per second
✓ for loop	11,366,692 Ops/sec
Object.fromPairs	2,534,788 Ops/sec
Array.reduce(...)	870,770 Ops/sec

Script Preparation code:

var xs = [
    ["foo1", "bar"],
    ["foo2", "bar"],
    ["foo3", "bar"],
    ["foo4", "bar"],
    ["foo5", "bar"],
    ["foo6", "bar"],
    ["foo7", "bar"],
    ["foo8", "bar"],
    ["foo9", "bar"],
    ["foo10", "bar"],
    ["foo11", "bar"],
    ["foo12", "bar"],
];

Tests:

Object.fromPairs
Object.fromEntries(xs)
Array.reduce(...)
xs.reduce((agg, [k, v]) => ({ ...agg, [k]: v }), {});
for loop
let r = {}; for (let i = 0; i < xs.length; i++) { r[xs[i][0]] = xs[i][1]; }

Run results for: fromEntries vs for vs reduce

Object creation from an array

Object.fromPairs

Array.reduce(...)

for loop