Run results for: for vs foreach vs some vs for..of vs for cached length non empty array actually check no break

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.0.0 Safari/537.36 Edg/75.0.131.0

Browser: Chrome 91

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
for	512.2 Ops/sec
for cached length	1023.2 Ops/sec
some	20157.3 Ops/sec
for..of	80157.4 Ops/sec
foreach	9209.5 Ops/sec

Script Preparation code:

var a = new Array(10000);


for(i=0; i<5000; i++){
    a[i] = ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c => (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16));
}
a[5000] = 1488;
for(i=5001; i<10000; i++){
    a[i] = ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c => (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16));
}

Tests:

for
var has1488 = false; for (var i = 0; i < a.length; i++) { if (a[i] === 1488) has1488 = true; }
for cached length
var has1488 = false; for (var i = 0, l=a.length; i < l; ++i) { if (a[i] === 1488) has1488 = true; }
some
var has1488 = a.some(function(i) { return i === 1488; });
for..of
var has1488 = false; for (var i of a) { if (i === 1488) has1488 = true; }
foreach
var has1488 = false; a.forEach(function(i) { if (i === 1488) has1488 = true; });

Run results for: for vs foreach vs some vs for..of vs for cached length non empty array actually check no break

Compare loop performance

for

for cached length

some

for..of

foreach