Benchmark: push vs index - MeasureThat.net

Tests:

push
const messages = (new Array(50000)).fill({hans: 'friedrich'}); const target = []; for (const msg of messages) target.push({ok: true});
index
const messages = (new Array(50000)).fill({hans: 'friedrich'}); const target = new Array(50000); for (let i = 0, len = messages.length; i < len; i++) target[i] = {ok: true};

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push
index

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Windows

View result in a separate tab

Test name	Executions per second
push	764.5 Ops/sec
index	1165.7 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and its results to explain what's being tested, compared, and analyzed.

**Benchmark Overview**

The benchmark compares two approaches for pushing elements onto an array: `target.push` (often referred to as "push" in JavaScript) and indexing into the array directly (`target[i] = {ok: true};`) with a fixed index. The test creates an array of 50,000 objects using `Array.prototype.fill()` and then pushes or indexes elements onto it.

**Library and Syntax**

There is no specific library being used in this benchmark. However, JavaScript's `Array.prototype.fill()` method is used to create the initial array. Additionally, the `for...of` loop (used in the "push" test case) and `for...let` loop (used in the "index" test case) are part of JavaScript's standard syntax.

**Approaches Compared**

The two approaches being compared are:

1. **Push**: Using the `target.push()` method to add elements to the array.
2. **Indexing**: Using indexing (`target[i] = {ok: true};`) with a fixed index to access and modify the array.

**Pros and Cons of Each Approach**

**Push**

Pros:

* Generally faster and more memory-efficient, as it avoids the overhead of indexing into the array.
* Can handle arrays of any size without performance degradation.

Cons:

* May lead to slower performance for very large arrays due to the need to allocate additional space in the array's internal buffer.

**Indexing**

Pros:

* Can be useful when working with fixed indices or specific elements within an array.
* Reduces memory usage compared to using `target.push()` with many elements.

Cons:

* Generally slower and less efficient, especially for large arrays.
* Requires indexing into the array, which can lead to performance overhead and increased memory usage.

**Considerations**

When deciding between `target.push()` and indexing, consider the following factors:

* Performance requirements: If speed is critical, using `target.push()` may be a better choice. However, if you need to access specific elements or work with large arrays, indexing might be more suitable.
* Memory constraints: If memory usage is a concern, indexing can help reduce it.

**Other Alternatives**

In JavaScript, other approaches for adding elements to an array include:

1. **Using `Array.prototype.concat()`**: This method concatenates multiple arrays into a new array. While faster than `target.push()`, it requires more overhead due to the creation of a new array.
2. **Using `Array.prototype splice()`**: This method modifies an existing array by adding or removing elements at a specified index. It's slower and less efficient than `target.push()`.
3. **Using `set()` (ES6+)**: The `set` collection allows you to add unique values to an array-like object without the need for indexing. However, it's not directly applicable to this specific benchmark.

Keep in mind that these alternatives may have different use cases and performance characteristics depending on your specific requirements.

Related benchmarks:

push vs index (version: 0)

Comparing performance of: push vs index

Created: 8 years ago by: Guest

Jump to the latest result

push

index

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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