Benchmark: lodash forEach vs for i loop with length cached vs Array#forEach

HTML Preparation code:

<script src="https://cdn.jsdelivr.net/lodash/4.16.0/lodash.min.js"></script>

Script Preparation code:

var values = [{a: 30310}, {b: 100303}, {c: 3040494}]

Tests:

lodash.forEach
var count = 0; _.forEach(values, function(v,i) { if (v.a != null) { count++; } })
native
var count = 0; for (var i = 0, len = values.length; i < len; i++) { if (values[i].a != null) { count++; } }
Array#forEach
var count = 0; values.forEach(function(v,i) { if (v.a != null) { count++; } })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash.forEach
native
Array#forEach

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to help you understand the provided benchmark.

**Benchmark Overview**

The benchmark compares three approaches for iterating over an array of objects in JavaScript:

1. `lodash.forEach`
2. A native `for` loop with length caching
3. The built-in `Array#forEach` method

**Options Compared**

Here's a brief overview of each option:

* **Lodash `forEach`**: A popular utility library that provides a convenient way to iterate over arrays and objects.
	+ Pros: Convenient, easy to use, widely adopted.
	+ Cons: Adds external dependency (lodash), can be slower due to function call overhead.
* **Native `for` loop with length caching**: A low-level approach that uses a traditional `for` loop to iterate over the array.
	+ Pros: No external dependencies, potentially faster due to less function call overhead.
	+ Cons: Requires manual memory management (length caching), can be more error-prone.
* **Array#forEach**: The built-in method for iterating over arrays in JavaScript.
	+ Pros: Native implementation, no external dependencies, concise syntax.
	+ Cons: May not be as efficient as a native `for` loop or lodash's implementation.

**Library - Lodash**

Lodash is a popular utility library for JavaScript that provides a wide range of functions for working with data structures, including arrays and objects. In this benchmark, the `forEach` method is used to iterate over an array of objects. Lodash adds a small overhead due to function call and object creation.

**JavaScript Special Feature - Iterators**

The `Array#forEach` method uses an iterator to iterate over the array. An iterator is an object that allows iteration over a collection of values, providing both the current value and its index (in this case). The use of an iterator enables efficient iteration over large arrays without creating intermediate arrays.

**Benchmark Preparation Code**

The script preparation code creates an array of three objects with properties `a`, `b`, and `c`. The benchmark uses this array as input for each test case.

**Test Case 1: Lodash `forEach`**

This test case iterates over the array using lodash's `forEach` method. It increments a counter (`count`) whenever it encounters an object with a non-null value in property `a`.

**Test Case 2: Native `for` loop with length caching**

This test case uses a traditional `for` loop to iterate over the array. The `length` property of the array is cached for each iteration, reducing overhead due to array lookups.

**Test Case 3: Array#forEach**

This test case uses the built-in `Array#forEach` method to iterate over the array. It increments a counter (`count`) whenever it encounters an object with a non-null value in property `a`.

**Other Alternatives**

Some other approaches for iterating over arrays in JavaScript include:

* Using the `map()` or `reduce()` methods, which are more suitable for transforming data rather than iterating.
* Using a `while` loop, which can be more efficient but requires manual memory management.
* Using an external library like jQuery, which provides its own iteration methods (e.g., `.each()`).

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0

Browser/OS: Firefox 68 on Windows

View result in a separate tab

Test name	Executions per second
lodash.forEach	7568431.0 Ops/sec
native	17900702.0 Ops/sec
Array#forEach	16789180.0 Ops/sec

Related benchmarks:

lodash forEach vs for i loop with length cached vs Array#forEach (version: 0)

Comparing performance of: lodash.forEach vs native vs Array#forEach

Created: 5 years ago by: Guest

Jump to the latest result

lodash.forEach

native

Array#forEach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):