Benchmark: native reverse find vs lodash _.findLast

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 }
]

Tests:

array find
// Native users.slice().reverse().find(function (o) { return o.age < 40; })
_.findLast
_.findLast(users, function (o) { return o.age < 40; })

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

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Overview**

The provided benchmark compares two approaches to find the last element in an array that satisfies a certain condition: the traditional `concat()` method and the new ES6 spread operator (`...`). The benchmark is designed to test the performance of these two approaches in JavaScript.

**Options Compared**

Two options are compared:

1. **Native (slice().reverse().find())**: This approach uses the native `Array.prototype.slice()`, reverses the array using `slice()` and the `reverse()` method, and then finds the last element that satisfies the condition using the `find()` method.
2. **Lodash (_.findLast())**: This approach uses the popular JavaScript library Lodash to find the last element in the array that satisfies the condition.

**Pros and Cons of Each Approach**

**Native (slice().reverse().find())**

Pros:

* Native implementation, which means it's likely to be optimized for performance.
* No additional dependencies or libraries required.

Cons:

* Requires manual array reversal, which can lead to unnecessary overhead.
* May not perform well on large arrays due to the overhead of reversing the entire array.

**Lodash (_.findLast())**

Pros:

* Optimized for performance by Lodash's authors.
* Simplifies the implementation and reduces code complexity.

Cons:

* Requires an additional library (Lodash) to be included, which may add overhead.
* May not provide optimal performance if the condition is complex or if the array is very large.

**Library: Lodash**

Lodash is a popular JavaScript library that provides a set of reusable functions for various tasks. In this case, `_findLast()` is used to find the last element in an array that satisfies a certain condition. The `_.` notation refers to the top-level namespace of the Lodash library.

**Special JS Feature/Syntax**

This benchmark does not use any special JavaScript features or syntax beyond the ES6 spread operator (`...`). However, it's worth noting that modern JavaScript engines and browsers support the new ES6 features, which can affect performance.

**Other Alternatives**

If you're interested in exploring alternative approaches, here are a few options:

1. **Underscore.js**: Another popular JavaScript library that provides similar functionality to Lodash.
2. **Array.prototype.reduce() + Array.prototype.findLast()**: An alternative implementation using `reduce()` and `findLast()` instead of the spread operator.
3. **Manual loop-based approach**: Implementing a custom loop-based solution to find the last element in the array.

Keep in mind that these alternatives may have different performance characteristics or complexity profiles, so it's essential to experiment and verify their results on your specific use case.

Latest run results:

Run details: (Test run date: 26 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36

Browser/OS: Chrome 129 on Windows

View result in a separate tab

Test name	Executions per second
array find	12415440.0 Ops/sec
_.findLast	4272588.0 Ops/sec

Related benchmarks:

native reverse find vs lodash _.findLast (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 28 days ago):