Benchmark: filter X findIndex

Script Preparation code:

window.testList = [
  { a: 'one', b: 1},
  { a: 'two', b: 2},
  { a: 'three', b: 3},
  { a: 'four', b: 4},
  { a: 'five', b: 5},
  { a: 'six', b: 6}
];

Tests:

filter
const [firstMatch] = window.testList.filter(({ a }) => a === 'four');
testList
const resultFilter = window.testList.findIndex(({ a }) => a === 'four'); const firstMatch = window.testList[resultFilter];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
filter
testList

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36

Browser/OS: Chrome 91 on Windows

View result in a separate tab

Test name	Executions per second
filter	3279124.8 Ops/sec
testList	1634279.8 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 is being tested.

**Benchmark Overview**

The benchmark consists of two test cases: `filter` and `testList`. Both test cases are designed to measure the performance of different approaches for filtering an array in JavaScript.

**Test Case 1: `filter`**

In this test case, the script preparation code defines a constant `window.testList`, which is an array of objects. The benchmark definition code is:
```javascript
const [firstMatch] = window.testList.filter(({ a }) => a === 'four');
```
This code uses the `Array.prototype.filter()` method to create a new array containing only the elements that match the condition `a === 'four'`. The `[firstMatch]` syntax is used to extract the first element of the filtered array into a constant.

**Pros and Cons:**

* Pros:
	+ This approach is concise and easy to read.
	+ It uses a built-in method, which is likely to be optimized for performance.
* Cons:
	+ The `filter()` method creates a new array, which can lead to increased memory usage.
	+ If the input array is very large, this approach might not be as efficient as other methods.

**Test Case 2: `testList`**

In this test case, the script preparation code defines a constant `window.testList`, which is an array of objects. The benchmark definition code is:
```javascript
const resultFilter = window.testList.findIndex(({ a }) => a === 'four');
const firstMatch = window.testList[resultFilter];
```
This code uses the `Array.prototype.findIndex()` method to find the index of the first element that matches the condition `a === 'four'`. The resulting index is stored in `resultFilter`, and then used to extract the corresponding element from the original array using bracket notation.

**Pros and Cons:**

* Pros:
	+ This approach avoids creating a new array, which reduces memory usage.
	+ It uses indexing directly, which can be faster than filtering.
* Cons:
	+ The code is slightly longer and more verbose than the `filter()` method approach.
	+ The use of bracket notation might lead to errors if the index is out of bounds.

**Library Used:**

Neither of these test cases uses a specific library. However, the benchmark definition code does rely on the built-in `Array.prototype.filter()` and `Array.prototype.findIndex()` methods, which are part of the JavaScript standard library.

**Special JS Features or Syntax:**

Neither of these test cases uses any special JavaScript features or syntax that would be unfamiliar to most software engineers. The code is straightforward and follows standard JavaScript conventions.

**Other Alternatives:**

There are other approaches for filtering an array in JavaScript, such as using `Array.prototype.map()` and `Array.prototype.reduce()`. For example:
```javascript
const firstMatch = window.testList.find(({ a }) => a === 'four');
```
This approach uses the `Array.prototype.find()` method to find the first element that matches the condition. The resulting element is stored in `firstMatch`.

Alternatively, you could use a library like Lodash or Ramda to perform filtering and other array operations.

In general, the choice of approach depends on the specific requirements of your project, such as performance, memory usage, and code readability.

Related benchmarks:

filter X findIndex (version: 0)

filter X findIndex

Comparing performance of: filter vs testList

Created: 3 years ago by: Guest

Jump to the latest result

filter

testList

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):