Benchmark: set.add vs array.push

Tests:

array.push
const a = [] for (let i = 0; i < 3000; i++) a.push(i)
set.add
const s = new Set() for (let i = 0; i < 3000; i++) s.add(i)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.push
set.add

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0

Browser/OS: Firefox 137 on Windows

View result in a separate tab

Test name	Executions per second
array.push	187252.0 Ops/sec
set.add	11099.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its test cases.

**What is being tested?**

The provided benchmark tests two different ways to add elements to an array or a Set data structure in JavaScript:

1. `array.push`: This method adds one element to the end of an array.
2. `set.add`: This method adds one element to a Set data structure.

These test cases aim to measure the performance difference between using `push` on arrays and `add` on Sets for large numbers of elements.

**Options compared**

The benchmark compares two approaches:

* **Array.push**: This is the traditional way of adding elements to an array in JavaScript. When you call `a.push(i)`, it adds the element `i` to the end of the array.
* **Set.add**: This method adds the element `i` to a Set data structure, which automatically removes any duplicates.

**Pros and Cons**

Here's a brief summary:

* **Array.push**:
	+ Pros: Simple, widely supported, and easy to understand. It works well for small to medium-sized arrays.
	+ Cons: For large arrays or datasets, `push` can lead to slower performance due to the need to reallocate memory and create new arrays.
* **Set.add**:
	+ Pros: Faster performance for large datasets since Sets only store unique elements. This makes it suitable for tasks like data deduplication or filtering.
	+ Cons: May not be suitable for small datasets where the overhead of creating a Set is unnecessary.

**Library and purpose**

In this benchmark, no external libraries are used beyond JavaScript's built-in `Set` and `Array` objects.

No special JavaScript features or syntax are required to run these tests. The focus is on the fundamental differences between `push` on arrays and `add` on Sets.

**Other alternatives**

For sets, you might consider using other data structures like:

* `Map`: A Map can be used as a set when keys are hashable and uniqueness is guaranteed.
* `WeakSet`: A WeakSet is similar to a Set but doesn't prevent properties from being garbage collected.

However, for simple use cases where performance matters, the built-in Set object is usually the best choice.

Related benchmarks:

set.add vs array.push (version: 0)

Comparing performance of: array.push vs set.add

Created: 5 years ago by: Registered User

Jump to the latest result

array.push

set.add

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):