Benchmark: native reverse find vs lodash _.findLast larger sample

HTML Preparation code:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.core.js"></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

var users = [
  { 'user': 'joey',  'age': 32 },
  { 'user': 'ross',    'age': 41 },
  { 'user': 'chandler', 'age': 39 },
    { 'user': 'joey',  'age': 32 },
  { 'user': 'ross',    'age': 41 },
  { 'user': 'chandler', 'age': 39 },
    { 'user': 'joey',  'age': 32 },
  { 'user': 'rachel',    'age': 25 },
  { 'user': 'chandler', 'age': 39 },
    { 'user': 'joey',  'age': 32 },
  { 'user': 'ross',    'age': 41 },
  { 'user': 'chandler', 'age': 39 },
    { 'user': 'joey',  'age': 32 },
  { 'user': 'ross',    'age': 41 },
  { 'user': 'chandler', 'age': 39 },
    { 'user': 'joey',  'age': 32 },
  { 'user': 'ross',    'age': 41 },
  { 'user': 'chandler', 'age': 39 }
]

Tests:

array find
// Native users.slice().reverse().find(function (o) { return o.age < 30; })
_.findLast
_.findLast(users, function (o) { return o.age < 30; })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array find
_.findLast

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Windows

View result in a separate tab

Test name	Executions per second
array find	4541406.5 Ops/sec
_.findLast	2197754.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared options, pros and cons, and other considerations.

**Benchmark Description**

The test aims to compare two approaches: using the new ES6 spread operator (`...`) with the traditional `concat()` method for finding an element in an array.

**Script Preparation Code**

The script prepares a large array of user objects with varying ages:
```javascript
var users = [
  { 'user': 'joey',  'age': 32 },
  { 'user': 'ross',    'age': 41 },
  { 'user': 'chandler', 'age': 39 },
  ...
];
```
The script preparation code is intentionally incomplete to force the use of either `...` or `concat()`.

**Html Preparation Code**

The HTML includes two JavaScript files:

1. `lodash.core.js`: a minified version of Lodash, which provides functional programming utilities.
2. `lodash.min.js`: another minified version of Lodash, specifically optimized for performance and size.

These libraries are used to make the test cases easier to write and maintain.

**Individual Test Cases**

There are two individual test cases:

1. **"array find"`**: This test case uses the new ES6 spread operator (`...`) to create a reversed copy of the array and then finds an element that meets the condition (`o.age < 30`).
2. **"_.findLast(users, function (o) { return o.age < 30; })"`**: This test case uses Lodash's `findLast` function to achieve the same result as the previous test case.

**Test Results**

The latest benchmark results show the execution performance of both test cases on a Chrome 121 browser on a Windows desktop:

1. **"array find"`**: 454,1406 executions per second
2. **"_.findLast"`: 219,7754 executions per second

**Comparison Options**

The two options being compared are:

* Using the new ES6 spread operator (`...`) with `concat()` to create a reversed copy of the array.
* Using Lodash's `findLast` function.

**Pros and Cons**

**Spread Operator (`...`) + concat()**

Pros:

* Uses modern JavaScript features, which may result in better code readability and maintainability.
* Can be more efficient for small arrays.

Cons:

* May not perform well on very large datasets due to the overhead of creating a reversed copy.
* Requires two function calls ( `slice()` and `concat()` ).

**Lodash's `findLast`**

Pros:

* Specifically optimized for performance and size, making it suitable for large datasets.
* Provides a simple and concise way to find the last element that meets the condition.

Cons:

* Uses an external library, which may add extra overhead.
* May require additional setup or imports in the test code.

**Other Considerations**

* The use of Lodash's `findLast` function may be seen as less "pure" JavaScript, as it relies on a third-party library. However, this can also be viewed as a trade-off for performance and convenience.
* The spread operator (`...`) is still a relatively new feature in JavaScript, and its performance might not be optimal yet.

**Alternatives**

If you prefer to avoid using external libraries or modern features, you could consider using other approaches, such as:

* Using `Array.prototype.indexOf()` or `Array.prototype.lastIndexOf()` to find the index of the last element that meets the condition.
* Creating a custom function or utility to achieve the same result.

Keep in mind that these alternatives might not provide the same level of performance and convenience as Lodash's `findLast` or the spread operator (`...`) with `concat()`.

Related benchmarks:

native reverse find vs lodash _.findLast larger sample (version: 0)

Compare the new ES6 spread operator with the traditional concat() method

Comparing performance of: array find vs _.findLast

Created: 4 years ago by: Guest

Jump to the latest result

array find

_.findLast

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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