Benchmark: findIndex vs for loop with plain number array

Script Preparation code:

var arr = new Array(15000);
arr.fill([ 500 ]);
arr = arr.map((el, idx) => el.id = idx);
var foo = Math.floor(Math.random() * 15000);

Tests:

findIndex
arr.findIndex((itm) => itm.id === foo);
for loop
for (let i = 0; i < arr.length; i++) { if (arr[i].id === foo) break; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
findIndex
for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Safari/605.1.15

Browser/OS: Safari 17 on Linux

View result in a separate tab

Test name	Executions per second
findIndex	134.5 Ops/sec
for loop	55.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the Benchmark Definition and test cases.

**Benchmark Overview**

The benchmark is designed to compare two approaches for finding an object in a large array:

1. Using the `findIndex` method with a callback function.
2. Using a traditional `for` loop.

**Options Compared**

The two options being compared are:

* `arr.findIndex((itm) => itm.id === foo);`: This is the `findIndex` method, which returns the index of the first element in the array that satisfies the provided condition.
* `for (let i = 0; i < arr.length; i++) { ... }`: This is a traditional `for` loop that iterates through the array and checks each element's `id` property.

**Pros and Cons**

* **findIndex method:**
	+ Pros:
		- More concise and readable code.
		- Less prone to errors due to the use of a callback function.
	+ Cons:
		- May be slower than traditional loops due to the overhead of the `findIndex` method.
		- Requires JavaScript 5 or later for syntax support.
* **Traditional `for` loop:**
	+ Pros:
		- Faster execution speed, as it avoids the overhead of the `findIndex` method.
		- More control over the iteration process.
	+ Cons:
		- More verbose and error-prone code due to the use of an explicit loop.

**Library**

In this benchmark, no libraries are explicitly mentioned. However, the `findIndex` method is a built-in JavaScript function that uses the V8 engine (specifically, SpiderMonkey) for its implementation.

**Special JS Feature or Syntax**

The benchmark utilizes the `let` and `const` keywords with block scope, which was introduced in ECMAScript 2015 (ES6). The `=>` symbol is used as an arrow function syntax. These features are not essential to understanding the benchmark but demonstrate modern JavaScript capabilities.

**Other Alternatives**

If you wanted to write a similar benchmark for this scenario, you could also use:

* `Array.prototype.some()`: This method returns `true` if at least one element in the array satisfies the condition.
* Using a regular expression with `String.prototype.indexOf()` or `String.prototype.search()`
* Utilizing `Buffer.find()` (for Node.js and other platforms that support it)

Related benchmarks:

findIndex vs for loop with plain number array (version: 0)

Testing finding an object array via findIndex or by using a for loop

Comparing performance of: findIndex vs for loop

Created: one year ago by: Guest

Jump to the latest result

findIndex

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):