Benchmark: Javascript loop - MeasureThat.net

Script Preparation code:

var arr = [];
for (var i = 0; i < 12345; i++) {
  arr[i] = i;
}

function someFn(i) {
  return (i * 3 * 8 / 1200 * 0.002 / 40 * 0.2);
}

var sumForEach = 0,
  sumReduce = 0,
  sumMap = 0,
  sumFilter = 0,
  sumFor = 0;

Tests:

forEach
arr.forEach(item => sumForEach += someFn(item));
some and forEach
arr.some(item => sumForEach += someFn(item)); arr.forEach(item => sumForEach += someFn(item));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
some and forEach

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what's being tested in this JavaScript microbenchmark.

**Benchmark Definition**

The benchmark defines a simple script that creates an array `arr` with 12,345 elements and assigns each element its index. It also defines a function `someFn` that takes an integer `i` as input and performs some arithmetic operations on it.

The script then sets up four variables: `sumForEach`, `sumReduce`, `sumMap`, and `sumFilter`. These variables will be used to measure the performance of different array iteration methods.

**Test Cases**

There are two test cases:

1. **forEach**: This test case measures the performance of the `arr.forEach()` method, which calls the callback function `someFn` for each element in the array.
2. **some and forEach**: This test case measures the performance of calling both `arr.some()` and `arr.forEach()` methods on the same array.

**Options Compared**

In this benchmark, we have four options compared:

1. `forEach`: This option uses the `arr.forEach()` method to iterate over the array.
2. `some`: This option uses the `arr.some()` method to filter out elements from the array before calling the callback function.
3. Both: This option calls both `arr.some()` and `arr.forEach()` methods on the same array.

**Pros and Cons**

Here's a brief analysis of each option:

* **forEach**:
	+ Pros: Simple and straightforward, easy to understand for developers familiar with JavaScript arrays.
	+ Cons: May be slower than other options due to unnecessary filtering and callback function overhead.
* **some**:
	+ Pros: Can eliminate unnecessary elements from the array before iterating over it, potentially leading to faster execution times.
	+ Cons: Requires an additional method call (`arr.some()`), which can incur additional overhead.
* **Both**:
	+ Pros: Can take advantage of the filtering power of `arr.some()` while still using the simple and familiar `forEach` method for iteration.
	+ Cons: May lead to unnecessary complexity due to the combination of two methods.

**Library: Lodash's `some()`**

In one of the test cases, the benchmark uses the `arr.some()` method. This method is part of the popular JavaScript utility library Lodash. It returns a boolean indicating whether at least one element in the array passes the provided condition.

**Special JS Feature or Syntax**

There are no special features or syntaxes used in this benchmark that require special explanation.

Now, let's look at the latest benchmark results:

The top two results show similar performance for both `forEach` and `some and forEach`. The Chrome Mobile 92 browser on Android 10 shows higher execution rates than other browsers.

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; SAMSUNG SM-J810G) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/16.0 Chrome/92.0.4515.166 Mobile Safari/537.36

Browser/OS: Chrome Mobile 92 on Android

View result in a separate tab

Test name	Executions per second
forEach	28.3 Ops/sec
some and forEach	28.3 Ops/sec

Related benchmarks:

Javascript loop (version: 0)

Comparing performance of: forEach vs some and forEach

Created: 4 months ago by: Registered User

Jump to the latest result

forEach

some and forEach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):