Run results for: shift and push vs slice

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

Browser: Chrome 110

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
spread shift and push	4893676.0 Ops/sec
slice spread and append	4391829.5 Ops/sec
slice and push	4764604.0 Ops/sec

Script Preparation code:

// obj from https://dev.to/saritchaethudis/working-with-complex-objects-in-javascript-the-friendly-beginners-guide-clh
var obj1 = {
    artPieces: [{
            pieceName: "Emo Flamingos",
            price: 30,
            ownerList: [{
                    name: "Fida Ernest",
                    userID: 23849,
                    purchaseDate: "09/13/2021",
                },
                {
                    name: "Eric Karger",
                    userID: 23510,
                    purchaseDate: "09/13/2021",
                },
            ],
        },
        {
            pieceName: "Where is my bit wallet",
            price: 100,
            ownerList: [],
        },
    ],
    storeCredits: 1000,
};

var obj2 = {
    name: "Rose Daniel",
    userID: 23849,
    purchaseDate: "11/29/2021",
};

var arr = [obj1, obj2, obj1, obj2, obj1, obj2, obj1, obj2, obj1, obj2, obj1, obj2, obj1, obj2, obj1, obj2, obj1, obj2];

Tests:

spread shift and push
let result = [...arr]; result.shift(); result.push(obj1);
slice spread and append
let result = [...arr.slice(1), obj1];
slice and push
let result = arr.slice(1); result.push(obj1);

Run results for: shift and push vs slice

spread shift and push

slice spread and append

slice and push