Benchmark: native reverse find vs native array findLast vs for loop find

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': 'joey',  'age': 32 },
  { 'user': 'ross',    'age': 41 },
  { 'user': 'joey',  'age': 32 },
  { 'user': 'ross',    'age': 41 },
  { '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; })
array findlast
users.slice().findLast(function (o) { return o.age < 40; })
for loop
let lastItem = undefined; for (let i = users.length - 1; i >= 0; i--) { if (users[i].age < 40) { lastItem = users[i]; break; // Exit the loop once the item is found } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array find
array findlast
for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:148.0) Gecko/20100101 Firefox/148.0

Browser/OS: Firefox 148 on Linux

View result in a separate tab

for loop

1063.9M/s

array findlast

28.6M/s

array find

21.1M/s

View exact numbers

Test name	Executions per second
✓ for loop	1,063,910,464 Ops/sec
array findlast	28,614,752 Ops/sec
array find	21,133,500 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark measures the performance of three different approaches to find an element in an array with specific conditions: using `array.find()`, `array.findLast()`, and a manual `for` loop.

**Test Cases**

There are three test cases:

1. **array find**: Uses `slice()` to create a copy of the original array, reverses it, and then finds the first element that satisfies the condition (`o.age < 40`) using the `find()` method.
2. **array findlast**: Uses `slice()` to create a copy of the original array, finds the last element that satisfies the condition (`o.age < 40`) using the `findLast()` method.
3. **for loop**: Iterates over the array in reverse order and checks each element's age until it finds one that is less than 40.

**Options Compared**

The benchmark compares the performance of:

* Using `array.find()` (Test Case 1)
* Using `array.findLast()` (Test Case 2)
* A manual `for` loop (Test Case 3)

**Pros and Cons of Each Approach**

1. **array find**:
	* Pros: Simple, readable, and easy to implement.
	* Cons: Creates a copy of the array, which can be memory-intensive for large datasets.
2. **array findlast**:
	* Pros: More efficient than `find()` since it only returns the last element that satisfies the condition, rather than searching the entire array.
	* Cons: May not work correctly if the array is empty or contains multiple elements with the same condition (in this case, no such issues).
3. **for loop**:
	* Pros: Highly customizable and can be optimized for specific use cases.
	* Cons: More verbose, error-prone, and may require additional memory to store variables.

**Libraries Used**

The benchmark uses two JavaScript libraries:

1. **Lodash**: The `find()` and `findLast()` methods are part of Lodash's utility functions. Lodash is a popular utility library that provides a wide range of functions for tasks like array manipulation, functional programming, and more.
2. **No additional libraries** are used in the manual `for` loop implementation.

**Special JavaScript Features/Syntax**

The benchmark uses the following special JavaScript features:

1. **Spread operator (`...`)**: Used in the `slice()` method to create a copy of the original array.
2. **Arrow functions**: Used in the `find()` and `findLast()` methods to define small, anonymous functions.

**Alternatives**

Other approaches to find an element in an array with specific conditions might include:

* Using `filter()`: Instead of finding a single element, you can use `filter()` to create a new array with all elements that satisfy the condition.
* Using a custom implementation with a separate function for each iteration: This approach would require manual memory management and may be more error-prone than using built-in methods like `find()` or `for` loops.

Keep in mind that the choice of approach depends on the specific requirements and constraints of your use case.

native reverse find vs native array findLast vs for loop find (version: 0)

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

Comparing performance of: `array find vs array findlast vs for loop`

Created: one year ago by: Guest

Go to the latest result

array find

array findlast

for loop

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

native reverse find vs native array findLast vs for loop find (version: 0)

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

Comparing performance of: array find vs array findlast vs for loop

Created: one year ago by: Guest

Go to the latest result

array find

array findlast

for loop

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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Comparing performance of: `array find vs array findlast vs for loop`