Simple deep equals implementation

objectUtilities.ts

// Largely based on the dequal package by lukeed, minus Date and RegExp capabilities: https://www.npmjs.com/package/dequal
// eslint-disable-next-line @typescript-eslint/no-explicit-any
export function deepEquals(foo: any, bar: any): boolean {
    let ctor, len: number;
    if (foo === bar) {
        return true;
    }

    if (foo && bar && (ctor = foo.constructor) === bar.constructor) {
        if (ctor === Array) {
            if ((len = foo.length) === bar.length) {
                while (len-- && deepEquals(foo[len], bar[len])) {}
            }
            return len === -1;
        }

        if (!ctor || typeof foo === 'object') {
            len = 0;
            for (ctor in foo) {
                if (
                    Object.prototype.hasOwnProperty.call(foo, ctor) &&
                    ++len &&
                    !Object.prototype.hasOwnProperty.call(bar, ctor)
                ) {
                    return false;
                }
                if (!(ctor in bar) || !deepEquals(foo[ctor], bar[ctor])) {
                    return false;
                }
            }
            return Object.keys(bar).length === len;
        }
    }

    return foo !== foo && bar !== bar;
}

/**
 * TESTS
 */

if (!deepEquals(1, 1)) {
    throw new Error();
} //=> true
if (!deepEquals({}, {})) {
    throw new Error();
} //=> true
if (!deepEquals('foo', 'foo')) {
    throw new Error();
} //=> true
if (!deepEquals([1, 2, 3], [1, 2, 3])) {
    throw new Error();
} //=> true
if (!deepEquals(deepEquals, deepEquals)) {
    throw new Error();
} //=> true
if (!deepEquals(null, null)) {
    throw new Error();
} //=> true
if (!deepEquals(NaN, NaN)) {
    throw new Error();
} //=> true
if (!deepEquals([], [])) {
    throw new Error();
} //=> true
if (!deepEquals([{ a: 1 }, [{ b: { c: [1] } }]], [{ a: 1 }, [{ b: { c: [1] } }]])) {
    throw new Error();
} //=> true
if (deepEquals(1, '1')) {
    throw new Error();
} //=> false
if (deepEquals(null, undefined)) {
    throw new Error();
} //=> false
if (deepEquals({ a: 1, b: [2, 3] }, { a: 1, b: [2, 5] })) {
    throw new Error();
} //=> false

console.log('Success!');