Run results for: for i < length vs .forEach(t) vs for..of vs for t = keys[i] vs for i =0; i in keys vs for i in object vs .reduce (keys only)

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:94.0) Gecko/20100101 Firefox/94.0

Browser: Firefox 94

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 2 years ago

Script Preparation code:

var object = {};
for (let i = 1; i <= 100000; i++) object[String(i)] = i;

Tests:

for..of
for (const k of Object.keys(object)) { window.k = k; }
for t = array[i]
for (let keys = Object.keys(object), i = -1, k; k = keys[++i];) { window.k = k; }
for i=0; i in array
for (let keys = Object.keys(object), i = -1; ++i in keys;) { window.k = keys[i]; }
for i in array,
for (const k in object) { window.k = k; }
.reduce
Object.keys(object).reduce((_, k) => { window.k = k; });