Benchmark: push vs index - MeasureThat.net

Tests:

push
const messages = (new Array(50000)).fill({hans: 'friedrich'}); const target = new Array(50000); 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: 4 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0

Browser/OS: Firefox 146 on Windows

View result in a separate tab

Test name	Executions per second
push	98.6 Ops/sec
index	828.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition and Purpose**

The benchmark definition is a JSON object that represents a specific test case. In this case, there are two test cases: "push" and "index". Both test cases aim to measure the performance difference between using the `push()` method versus indexing into an array.

**Push vs Index Approach**

The push approach uses the `push()` method to add elements to the target array, while the index approach uses direct indexing (`target[i] = {ok: true};`) to assign values to the array.

**Pros and Cons of Each Approach**

* **Push Method:**
	+ Pros:
		- Efficient for adding a large number of elements to an array from the end.
		- Can be faster for sparse arrays or arrays with many empty slots.
	+ Cons:
		- Slower for inserting elements at specific indices, as it requires shifting all subsequent elements down.
		- May not perform well on small arrays due to overhead of creating a new element and pushing it onto the array.
* **Indexing Approach:**
	+ Pros:
		- Faster for inserting elements at specific indices, as it avoids the need to shift elements down.
		- More efficient for large arrays with many empty slots.
	+ Cons:
		- Slower for adding a large number of elements to an array from the end, as it requires indexing into the array.

**Library and Special JS Features**

In this benchmark, there is no specific library used. However, JavaScript features like `const` declarations, arrow functions (`=>`), and template literals (`\r\n`) are not mentioned in either test case. These features are a part of modern JavaScript syntax and may affect the performance or behavior of the code.

**Considerations**

When writing benchmarks, it's essential to consider factors that might impact performance, such as:

* Array size: Larger arrays can lead to more cache misses, which can slow down push-based operations.
* Data type: Using objects with large properties or complex data structures can increase overhead and slow down indexing-based operations.
* Browser and environment differences: Different browsers may have varying optimizations for array operations, leading to performance disparities.

**Other Alternatives**

If you're interested in exploring alternative approaches or test cases, here are a few suggestions:

* **Array.prototype.splice()**: This method combines the benefits of both push and indexing approaches. It inserts elements at specific indices while maintaining the original array's structure.
* **Typed Arrays**: For large arrays with homogeneous data types, using typed arrays (e.g., `Uint8Array`) can provide better performance and reduced memory usage compared to native JavaScript arrays.
* **Native WebAssembly (WASM) arrays**: For highly optimized and low-level array operations, consider using WASM arrays, which are designed for high-performance computing.

Keep in mind that the choice of approach or alternative depends on the specific use case and requirements. Experimenting with different scenarios can help you find the most efficient solution for your particular problem.

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):