Run results for: for-in vs for-of

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:89.0) Gecko/20100101 Firefox/89.0

Browser: Firefox 89

Operating system: Linux

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
for-of	10727.3 Ops/sec
for-in	28189.2 Ops/sec

Script Preparation code:

var DATA = {};
for (let i = 0; i < 1000; i++) {
  DATA["some-property-name-" + i] = "some-property-value-" + i;
}

function PROCESS(property, value) {
}

Tests:

for-of
for (const [key, value] of Object.entries(DATA)) { PROCESS(key, value); }
for-in
for (const key in DATA) { const value = DATA[key]; PROCESS(key, value); }