Run results for: Lodash isEqual compare with custom deepEqual in compare objects

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36

Browser: Chrome 89

Operating system: Mac OS X 11.2.1

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
_.isEqual Level 1	455833.1 Ops/sec
deepEquals Level 1	1871585.0 Ops/sec
_.isEqual Level 2	279389.6 Ops/sec
deepEquals Level 2	1486872.2 Ops/sec
_.isEqual Level 3	208318.7 Ops/sec
deepEquals Level 3	1263887.4 Ops/sec

HTML Preparation code:

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.4/lodash.min.js"></script>
<script>
  
  function deepEquals(x, y, exceptionName) {
    if (x === y) {
        return true; // if both x and y are null or undefined and exactly the same
    }
    else if (!(x instanceof Object) || !(y instanceof Object)) {
        return false; // if they are not strictly equal, they both need to be Objects
    }
    else if (x.constructor !== y.constructor) {
        // they must have the exact same prototype chain, the closest we can do is
        // test their constructor.
        return false;
    }
    else {
        for (const p in x) {
            if (!x.hasOwnProperty(p)) {
                continue; // other properties were tested using x.constructor === y.constructor
            }
            if (!y.hasOwnProperty(p)) {
                return false; // allows to compare x[ p ] and y[ p ] when set to undefined
            }
            if (x[p] === y[p] || (!!exceptionName && p === exceptionName)) {
                continue; // if they have the same strict value or identity then they are equal
            }
            if (typeof x[p] !== 'object') {
                return false; // Numbers, Strings, Functions, Booleans must be strictly equal
            }
            if (!deepEquals(x[p], y[p])) {
                return false;
            }
        }
        for (const p in y) {
            if (y.hasOwnProperty(p) && !x.hasOwnProperty(p)) {
                return false;
            }
        }
        return true;
    }
}
</script>

Script Preparation code:

// 1 level deep
window.foo1 = { a: 1, b: 2, c: { a: 1, b: 2, c: { a: 1, b: 2 } } };
window.bar1 = { a: 1, b: 3, c: { a: 1, b: 2, c: { a: 1, b: 2 } } };

// 2 levels deep
window.foo2 = { a: 1, b: 2, c: { a: 1, b: 2, c: { a: 1, b: 2 } } };
window.bar2 = { a: 1, b: 2, c: { a: 1, b: 3, c: { a: 1, b: 2 } } };

// 3 levels deep
window.foo3 = { a: 1, b: 2, c: { a: 1, b: 2, c: { a: 1, b: 2 } } };
window.bar3 = { a: 1, b: 2, c: { a: 1, b: 2, c: { a: 1, b: 4 } } };

Tests:

_.isEqual Level 1
_.isEqual(window.foo1, window.bar1)
deepEquals Level 1
deepEquals(window.foo1, window.bar1);
_.isEqual Level 2
_.isEqual(window.foo2, window.bar2)
deepEquals Level 2
deepEquals(window.foo2, window.bar2);
_.isEqual Level 3
_.isEqual(window.foo3, window.bar3)
deepEquals Level 3
deepEquals(window.foo3, window.bar3);

Run results for: Lodash isEqual compare with custom deepEqual in compare objects

Test on isEqual performance

_.isEqual Level 1

deepEquals Level 1

_.isEqual Level 2

deepEquals Level 2

_.isEqual Level 3

deepEquals Level 3