Run results for: fast Deep Equal vs JSON.stringify Equality Comparison for very large arrays of nested numbers

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser: Chrome 136

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
fast deep equals same	710.4 Ops/sec
fast deep equals similar	887.2 Ops/sec
fast deep equals different	17808730.0 Ops/sec
stringify same	29.1 Ops/sec
stringify similar	29.7 Ops/sec
stringify different	31.3 Ops/sec

Script Preparation code:

'use strict';

// do not edit .js files directly - edit src/index.jst


var envHasBigInt64Array = typeof BigInt64Array !== 'undefined';


window.fdeq = function equal(a, b) {
    if (a === b) return true;

    if (a && b && typeof a == 'object' && typeof b == 'object') {
        if (a.constructor !== b.constructor) return false;

        var length, i, keys;
        if (Array.isArray(a)) {
            length = a.length;
            if (length != b.length) return false;
            for (i = length; i-- !== 0;)
                if (!equal(a[i], b[i])) return false;
            return true;
        }


        if ((a instanceof Map) && (b instanceof Map)) {
            if (a.size !== b.size) return false;
            for (i of a.entries())
                if (!b.has(i[0])) return false;
            for (i of a.entries())
                if (!equal(i[1], b.get(i[0]))) return false;
            return true;
        }

        if ((a instanceof Set) && (b instanceof Set)) {
            if (a.size !== b.size) return false;
            for (i of a.entries())
                if (!b.has(i[0])) return false;
            return true;
        }

        if (ArrayBuffer.isView(a) && ArrayBuffer.isView(b)) {
            length = a.length;
            if (length != b.length) return false;
            for (i = length; i-- !== 0;)
                if (a[i] !== b[i]) return false;
            return true;
        }


        if (a.constructor === RegExp) return a.source === b.source && a.flags === b.flags;
        if (a.valueOf !== Object.prototype.valueOf) return a.valueOf() === b.valueOf();
        if (a.toString !== Object.prototype.toString) return a.toString() === b.toString();

        keys = Object.keys(a);
        length = keys.length;
        if (length !== Object.keys(b).length) return false;

        for (i = length; i-- !== 0;)
            if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;

        for (i = length; i-- !== 0;) {
            var key = keys[i];

            if (!equal(a[key], b[key])) return false;
        }

        return true;
    }

    // true if both NaN, false otherwise
    return a !== a && b !== b;
};

window.foo = Array.from({
    length: 40000
}, () => ([Math.random() * 40, Math.random() * 40]));
window.foo2 = JSON.parse(JSON.stringify(window.foo.slice()));
window.fox = (Array.from({
    length: 10000
}, () => ([Math.random() * 40, Math.random() * 40]))).concat(JSON.parse(JSON.stringify(window.foo.slice(-30000))));
window.bar = Array.from({
    length: 40000
}, () => ([Math.random() * 40, Math.random() * 40]));

Tests:

fast deep equals same
fdeq(window.foo, window.foo2);
fast deep equals similar
fdeq(window.foo, window.fox);
fast deep equals different
fdeq(window.foo, window.bar);
stringify same
JSON.stringify(window.foo) === JSON.stringify(window.foo2)
stringify similar
JSON.stringify(window.foo) === JSON.stringify(window.fox)
stringify different
JSON.stringify(window.foo) === JSON.stringify(window.bar)

Run results for: fast Deep Equal vs JSON.stringify Equality Comparison for very large arrays of nested numbers

Test on deep equality checking performance

fast deep equals same

fast deep equals similar

fast deep equals different

stringify same

stringify similar

stringify different