Run results for: compare content of two objects using Object.entries VS for...in

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

Browser: Chrome 79

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
Object.entries	2186.4 Ops/sec
Object for..in	4334.8 Ops/sec
Object for..in #2	5610.7 Ops/sec
Object for..in #3	4936.2 Ops/sec

Script Preparation code:

function makeid() {
    var text = "";
    var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

    for (var i = 0; i < 5; i++)
        text += possible.charAt(Math.floor(Math.random() * possible.length));

    return text;
}

window.parentObj = {};

const samples = 1000;

const a = {};

for (let i = 0; i < samples; i++) {
    a[makeid()] = makeid();
}

const b = JSON.parse(JSON.stringify(a));

const c = {};

for (let i = 0; i < samples; i++) {
    c[makeid()] = makeid();
}

window.parentObj = {a: a, b: b, c: c};

Tests:

Object.entries
const a = window.parentObj.a; const b = window.parentObj.b; const entries = Object.entries(a); const isNotEqual = entries.some(([k, v], i) => b[k] != v); if (isNotEqual) return false; return entries.length === Object.keys(b).length;
Object for..in
const a = window.parentObj.a; const b = window.parentObj.b; for(var key in a) { if (a[key] != b[key]) return false; }; return Object.keys(a).length === Object.keys(b).length;
Object for..in #2
const a = window.parentObj.a; const b = window.parentObj.b; let lengthA = 0; for(var key in a) { lengthA = lengthA + 1; if (a[key] != b[key]) return false; }; return lengthA === Object.keys(b).length;
Object for..in #3
const a = window.parentObj.a; const b = window.parentObj.b; let lengthA = 0; for(var key in a) { lengthA = lengthA + 1; if (a[key] != b[key]) return false; }; let lengthB = 0; for(var key in b) { lengthB = lengthB + 1; }; return lengthA === lengthB;

Run results for: compare content of two objects using Object.entries VS for...in

Object.entries

Object for..in

Object for..in #2

Object for..in #3