Run results for: immutable vs mutable, slice VS splice VS shift for fixed size arrays

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36 Edg/114.0.1823.82

Browser: Chrome 114

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Script Preparation code:

var count = 120000;
var list = new Array(count).fill(100);

Tests:

slice immutable
if (list.length > count - 1) { list=list.slice(0, count - 1) list.push(count + 1) } else { list = [...list, count + 1]; }
splice immutable
list = [...list, count + 1] if (list.length > count) { list.splice(0, list.length - count); }
shift-while immutable
list = [...list, count + 1] while (list.length > count) { list.shift(); }
slice mutable
list=list.slice(0, count) list.push(count + 1)
splice mutable
list.push(count + 1) if (list.length > count) { list.splice(0, list.length - count); }
shift-while mutable
list.push(count + 1) while (list.length > count) { list.shift(); }