Run results for: Array forEach callback function as a parameter vs as a predefined variable + compared to using callback parameters vs without + for..of, for..in, for loop

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0

Browser: Firefox 133

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

for..in

44.9M/s

for loop

12.3M/s

Array forEach, callback function provided as an argument, ignoring most callback arguments

6.8M/s

Array forEach, callback function provided as an argument

6.7M/s

Array forEach, callback function provided as a predefined variable

6.1M/s

for..of

847K/s

View exact numbers

Test name	Executions per second
✓ for..in	44,852,252 Ops/sec
for loop	12,345,011 Ops/sec
Array forEach, callback function provided as an argument, ignoring most callback arguments	6,758,680 Ops/sec
Array forEach, callback function provided as an argument	6,724,178 Ops/sec
Array forEach, callback function provided as a predefined variable	6,077,650 Ops/sec
for..of	846,731 Ops/sec

Script Preparation code:

var array = new Array(100);

var fn = function(el, idx, arr) {
  el;
}

Tests:

Array forEach, callback function provided as an argument, ignoring most callback arguments
array.forEach(function(_el, idx, _arr) { array[idx]; });
Array forEach, callback function provided as an argument
array.forEach(function(el, idx, arr) { el; });
Array forEach, callback function provided as a predefined variable
array.forEach(fn);
for..of
for (const i of array) { array[i]; }
for..in
for (var i in array) { array[i]; }
for loop
for (var i = 0; i < array.length; i++) { array[i]; }