Benchmark: foreach vs some and filter

HTML Preparation code:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.core.js"></script>

Tests:

foreach
var a = ['hello', 'a', 'bc','d','e','f','sdf']; var result = false; a.forEach(i=>{ if(i==='bc') { result = true; } });
some
var a = ['hello', 'ae', 'bc','d','e','f','sdf']; var b = a.some(item => item === 'bc'); var c = a.filter(item => item.includes('e'));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
some

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:104.0) Gecko/20100101 Firefox/104.0

Browser/OS: Firefox 104 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
foreach	39118744.0 Ops/sec
some	3816060.5 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

I'd be happy to help explain the benchmark and its results.

**What is being tested?**

The provided JSON represents two test cases that compare the performance of three different approaches: `forEach`, `some`, and `filter`. The test case uses JavaScript's Array methods to iterate over an array of strings and perform a specific operation on each element.

**Options compared**

The benchmark compares the following options:

1. **`forEach`**: A method that iterates over an array, executing a provided callback function for each element.
2. **`some`**: A method that returns `true` as soon as at least one element in the array satisfies a provided condition.
3. **`filter`**: A method that creates a new array with all elements that pass a test implemented by a provided function.

**Pros and Cons of each approach**

1. **`forEach`**:
	* Pros: Can be used to iterate over arrays and perform operations on each element, allowing for more control over the iteration process.
	* Cons: Can be slower than other methods because it requires creating an execution context for each callback function call, which can lead to overhead due to the need to set up and tear down local scope variables (e.g., `var i = 0;`) in modern JavaScript engines.
2. **`some`**:
	* Pros: Faster than `forEach` because it stops iterating as soon as a condition is met, reducing unnecessary iterations.
	* Cons: Returns `true` if any element satisfies the condition, so you need to be careful with your usage and potential side effects of modifying arrays during iteration.
3. **`filter`**:
	* Pros: Creates a new array, so it doesn't modify the original array (which is usually desirable). Also, it's generally faster than `forEach` because it can take advantage of hardware optimizations for creating arrays.
	* Cons: Returns an empty array if no elements satisfy the condition.

**Library and syntax**

The benchmark uses the Lodash library, which provides a concise implementation of these methods. The syntax used is specific to Lodash, but generally follows standard JavaScript conventions.

The use of `=>` (an arrow function) in the benchmark code is a feature introduced in ECMAScript 2015 (ES6). It allows for more concise and readable way of defining functions without explicitly declaring them with the `function` keyword. This syntax was widely adopted in modern JavaScript development, making it easier to write code that reads well.

**Other alternatives**

In addition to these methods, there are other approaches you could use to iterate over an array:

* **Manual indexing**: Use a traditional `for` loop and index into the array.
* **Using `map()` or `reduce()`: Both of which can be used for different purposes (like transforming data in `map()` or reducing a sum in `reduce()`).

Related benchmarks:

foreach vs some and filter (version: 0)

Comparing performance of: foreach vs some

Created: 2 years ago by: Guest

Jump to the latest result

foreach

some

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):