Benchmark: findIndex vs forEach

Script Preparation code:

var arr = new Array(15000);
arr.fill({ id: 0 });
arr = arr.map((el, idx) => el.id = idx);
var foo = Math.floor(Math.random() * 15000);
arr = arr.filter((value, index, self) => self.indexOf(value) === index)

Tests:

findIndex
const index = arr.findIndex((itm) => itm.id === foo); arr.splice(index,1);
forEach
arr.forEach((value, index) => { if (value.id === foo) { arr.splice(index, 1); } });

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

forEach

78.0M/s

findIndex

395K/s

Fastest: forEach (197.7x faster)

View exact numbers

✓ forEach: 78,042,440 ops/sec
• findIndex: 394,849 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
findIndex
forEach

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Mac OS X 10.15.7

View result in a separate tab

forEach

102.0M/s

findIndex

395K/s

View exact numbers

Test name	Executions per second
✓ forEach	101,950,408 Ops/sec
findIndex	394,849 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided JSON.

**Benchmark Description**
The benchmark compares the performance of two JavaScript methods: `Array.prototype.findIndex()` and `Array.prototype.forEach()`. The goal is to find the index of the first element that satisfies a certain condition and then remove that element from the array.

**Options Compared**

1. **FindIndex**: Uses the `findIndex()` method, which returns the index of the first element in the array that satisfies the provided testing function. If no elements satisfy the testing function, -1 is returned.
2. **ForEach**: Uses the `forEach()` method, which executes a provided function for each element in the array. In this case, we use it to find the first element that satisfies the condition and then remove it from the array.

**Pros and Cons**

* **FindIndex**:
	+ Pros: Generally faster than `forEach` because it uses an optimized algorithm that stops searching as soon as it finds a match.
	+ Cons: Returns -1 if no elements satisfy the testing function, which might require additional checks in your code.
* **ForEach**:
	+ Pros: More flexible and can be used for more complex operations than just finding and removing a single element.
	+ Cons: Generally slower than `findIndex` because it needs to iterate over all elements in the array.

**Other Considerations**

* **Performance**: As mentioned earlier, `findIndex` is generally faster than `forEach`. However, the actual performance difference depends on the specific use case and the size of the input array.
* **Readability and Maintainability**: Choose the method that best fits your code's logic and readability requirements.

**Library/Functionality Used**

In this benchmark, no external libraries are used. The JavaScript methods `Array.prototype.findIndex()` and `Array.prototype.forEach()` are part of the standard library.

**Special JS Features/Syntax**

There is no special JavaScript feature or syntax being tested in this benchmark. Both `findIndex` and `forEach` are standard methods that can be used with any array.

**Alternatives**

Other alternatives for finding the index of a single element in an array could include:

* Using the `indexOf()` method, which returns the index of the first occurrence of a specified value.
* Using the `search()` method, which searches the array from the start and returns the index of the first match.
* Implementing a custom search algorithm using loops or other optimization techniques.

However, these alternatives are not being tested in this specific benchmark.

findIndex vs forEach (version: 0) Benchmark.js

compare performance of findIndex and forEach in removing the first result in an array

Comparing performance of: `findIndex vs forEach`

Created: 3 years ago by: Registered User

Go to the latest result

findIndex

forEach

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

findIndex vs forEach (version: 0) Benchmark.js

compare performance of findIndex and forEach in removing the first result in an array

Comparing performance of: findIndex vs forEach

Created: 3 years ago by: Registered User

Go to the latest result

findIndex

forEach

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

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: `findIndex vs forEach`