Run results for: descending for vs cached for ++i loop (holey elements)

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:97.0) Gecko/20100101 Firefox/97.0

Browser: Firefox 97

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
descending	5090.5 Ops/sec
cached	2518.2 Ops/sec

Script Preparation code:

var k = [12,32,1312,312,"asdsad",NaN,null,undefined,new Map(), new Object(), {}, [],[[1]], "zzzzz", {}];
k = k.concat(new Array(1000)); //holey elements in V8

Tests:

descending
for (let i = k.length; i--;) { k[i] = k[i] + "z"; };
cached
for (let i = 0, len = k.length; i < len; ++i) { k[i] = k[i] + "z"; };

Run results for: descending for vs cached for ++i loop (holey elements)

(forEach + for-in do not iterate over empty array slots)

descending

cached