Benchmark: Object arrays: findIndex vs for loop2

Script Preparation code:

var arr = [...new Array(15000)].map((el, idx) => ({
    id: idx
}));

Tests:

findIndex
const foo = Math.floor(Math.random() * 15000); arr.findIndex((itm) => itm.id === foo);
for loop
const foo = Math.floor(Math.random() * 15000); for (let i = 0, j = arr.length; i < j; ++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: 2 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser/OS: Chrome 103 on Linux

View result in a separate tab

Test name	Executions per second
findIndex	120265.6 Ops/sec
for loop	2929.1 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 is designed to compare two approaches for finding an object in an array: using the `findIndex` method or a traditional `for` loop.

**Script Preparation Code**

The script preparation code creates an array of 15,000 objects with an "id" property:
```javascript
var arr = [...new Array(15000)].map((el, idx) => ({ id: idx }));
```
This array is used as the input for both test cases.

**Html Preparation Code**

There is no HTML preparation code provided, which means that this benchmark is purely JavaScript-based and does not involve any DOM manipulation or rendering.

**Test Cases**

The two test cases are:

1. `findIndex`:
```javascript
const foo = Math.floor(Math.random() * 15000);
arr.findIndex((itm) => itm.id === foo);
```
This test case uses the `findIndex` method to find an object in the array with a matching "id". The `foo` variable is randomly generated and used as the target value.

2. `for loop`:
```javascript
const foo = Math.floor(Math.random() * 15000);
for (let i = 0, j = arr.length; i < j; ++i) {
  if (arr[i].id === foo) break;
}
```
This test case uses a traditional `for` loop to iterate through the array and find an object with a matching "id". Again, the `foo` variable is randomly generated and used as the target value.

**Pros and Cons**

Here are some pros and cons of each approach:

* **findIndex**: Pros:
	+ More concise and expressive code
	+ Often faster due to the use of native optimization
*   Cons:
    * May not work correctly if the array is very large or sorted in a specific way.
*   for loop: Pros:
    * Can be more predictable and easy to understand for developers familiar with traditional loops
    * Works well for small to medium-sized arrays
*   Cons:
    * More verbose code compared to findIndex
    * May not be as fast due to the overhead of the loop

**Library and Special JS Features**

There is no library used in this benchmark. The `findIndex` method is a native JavaScript function that has been supported since ECMAScript 2012.

**Other Considerations**

When designing benchmarks, it's essential to consider factors such as:

* Input size: In this case, the input array is relatively small (15,000 objects). For larger inputs, other considerations like cache efficiency and memory allocation may become important.
* Loop unrolling or optimization: Some JavaScript engines can optimize loops, which might affect the results of this benchmark.
* Context: The benchmark assumes a modern browser environment with decent hardware. Results may vary in other contexts, such as older browsers or low-end devices.

**Alternatives**

Other alternatives for finding an object in an array include:

* `forEach`: While not designed specifically for finding elements, `forEach` can be used in combination with a callback function to achieve similar results.
* Array methods like `some`, `every`, or `filter`, which may have different performance characteristics depending on the use case.

Keep in mind that this benchmark is focused on comparing two specific approaches, rather than exploring other optimization techniques or considering broader performance implications.

Related benchmarks:

Object arrays: findIndex vs for loop2 (version: 0)

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

Comparing performance of: findIndex vs for loop

Created: 2 years ago by: Guest

Jump to the latest result

findIndex

for loop

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):