Benchmark: Test on isEqual and fastEqual false performance

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

window.foo = { arr: [1, 3], num: 12, o: { name: 'foo' }, quantum: [{ spin: 'x' }, { spin: 'y' }]};
window.bar = { arr: [1, 2], num: 12, o: { name: 'foo' }, quantum: [{ spin: 'x' }, { spin: 'y' }]};

var isArray = Array.isArray;
var keyList = Object.keys;
var hasProp = Object.prototype.hasOwnProperty;

function fastEqual(a, b) {
  if (a === b) return true;

  if (a && b && typeof a == 'object' && typeof b == 'object') {
    var arrA = isArray(a)
      , arrB = isArray(b)
      , i
      , length
      , key;

    if (arrA && arrB) {
      length = a.length;
      if (length != b.length) return false;
      for (i = length; i-- !== 0;)
        if (!fastEqual(a[i], b[i])) return false;
      return true;
    }

    if (arrA != arrB) return false;

    var dateA = a instanceof Date
      , dateB = b instanceof Date;
    if (dateA != dateB) return false;
    if (dateA && dateB) return a.getTime() == b.getTime();

    var regexpA = a instanceof RegExp
      , regexpB = b instanceof RegExp;
    if (regexpA != regexpB) return false;
    if (regexpA && regexpB) return a.toString() == b.toString();

    var keys = keyList(a);
    length = keys.length;

    if (length !== keyList(b).length)
      return false;

    for (i = length; i-- !== 0;)
      if (!hasProp.call(b, keys[i])) return false;

    for (i = length; i-- !== 0;) {
      key = keys[i];
      if (!fastEqual(a[key], b[key])) return false;
    }

    return true;
  }

  return a!==a && b!==b;
};

window.fastEqual = fastEqual;

Tests:

_.isEqual
_.isEqual(window.foo, window.bar)
JSON.stringify
JSON.stringify(window.foo) === JSON.stringify(window.bar);
fastEqual
window.fastEqual(window.foo, window.bar);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
_.isEqual
JSON.stringify
fastEqual

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

The provided JSON represents a JavaScript microbenchmark on MeasureThat.net, which compares the performance of three functions: `_.isEqual` from the Lodash library, `JSON.stringify`, and a custom implementation called `fastEqual`.

**What is being tested?**

The benchmark tests the performance of these three functions in comparing two objects, `window.foo` and `window.bar`. The comparison includes checks for:

* Deep object equality (e.g., arrays, objects)
* Date comparisons
* RegExp comparisons
* String comparisons

**Options compared:**

1. **_.isEqual**: A function from the Lodash library that performs deep object equality.
2. **JSON.stringify**: A built-in JavaScript function that converts an object to a string representation.
3. **fastEqual**: A custom implementation provided in the benchmark code, which uses various checks to compare two objects.

**Pros and Cons of each approach:**

1. **_.isEqual**: Pros:
	* Fast and efficient for deep object comparisons
	* Handles complex data structures like arrays and objects
Cons:
	* Dependent on the Lodash library, which may not be suitable for all use cases
2. **JSON.stringify**: Pros:
	+ Easy to implement and understand
	+ Works well for simple object comparisons
Cons:
	+ Inefficient for deep object comparisons (as it creates a new string representation)
	+ Not suitable for comparing complex data structures like arrays and objects
3. **fastEqual**: Pros:
	* Custom implementation that can be optimized for specific use cases
	* Handles various data types, including arrays, objects, dates, and RegExps
Cons:
	* More complex and harder to understand than _.isEqual or JSON.stringify
	+ Requires more CPU cycles due to the custom implementation

**Other considerations:**

* The `fastEqual` implementation uses a combination of checks to compare two objects. While it provides a high degree of accuracy, it may not be suitable for all use cases.
* The benchmark results show that `_.isEqual` is the fastest function in this comparison, followed by `JSON.stringify`, and then `fastEqual`.

**Alternative approaches:**

1. **ES6 Object Compare**: If you're using modern JavaScript versions, you can use the built-in `Object.is()` method to compare objects.
2. **Recursive Object Comparison Libraries**: There are libraries like `compare-objects` or `deep-equal` that provide more advanced object comparison features.

In summary, the choice of which function to use depends on your specific requirements and performance constraints. If you need a simple and efficient way to compare objects, _.isEqual might be a good option. However, if you need more control over the comparison process or are dealing with complex data structures, fastEqual or custom implementation might be more suitable.

Related benchmarks:

Test on isEqual and fastEqual false performance (version: 2)

Comparing performance of: _.isEqual vs JSON.stringify

Comparing performance of: _.isEqual vs JSON.stringify vs fastEqual

Created: 7 years ago by: Registered User

Jump to the latest result

_.isEqual

JSON.stringify

fastEqual

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):