Benchmark: push vs index123

Tests:

Array.push
const elements = document.all; const amount = elements.length; const arr = []; for (let i = 0; i < amount; i += 1) arr.push(elements[i]);
Array[index]
const elements = document.all; const amount = elements.length; const arr = []; for (let i = 0; i < amount; i += 1) arr[i] = elements[i];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.push
Array[index]

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36

Browser/OS: Chrome 143 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.push	2152859.0 Ops/sec
Array[index]	2125299.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmarking test cases and explain what's being tested, compared, and considered.

**Benchmark Definition**

The provided JSON defines two benchmark tests:

1. `push vs index123`
2. `Array.push` (individual test case)
3. `Array[index]` (individual test case)

**What is being tested?**

In general, the benchmarks are testing how different JavaScript approaches affect the performance of a specific operation: accessing and modifying elements in an array.

The two individual test cases:

* `Array.push`: Measures the time it takes to push a large number of elements onto an empty array.
* `Array[index]`: Measures the time it takes to access elements in an array by their index, without pushing new elements onto the array.

**Options compared**

In both test cases, two approaches are being compared:

1. **Push-based approach**: The array is initialized with a large number of dummy elements (e.g., `document.all`) and then pushed new elements onto the end of the array using `arr.push(elements[i])`.
2. **Index-based access**: The array is initialized with a large number of dummy elements, but instead of pushing new elements, individual elements are accessed directly by their index: `arr[i] = elements[i]`.

**Pros and Cons**

**Push-based approach (Array.push)**

Pros:

* This method can be used when you need to add multiple elements to the end of an array.
* It may be more efficient if the array is already large, as it avoids the overhead of accessing individual elements.

Cons:

* Creating a new element for each push operation can lead to increased memory allocation and garbage collection overhead.
* This method can lead to slower performance due to the repeated accesses to `elements[i]`.

**Index-based access (Array[index])**

Pros:

* This method is more efficient when you need to access individual elements by their index, as it avoids the overhead of creating new elements.
* It may be faster for large arrays with many fixed-size indices.

Cons:

* If the array contains a small number of elements or if the index calculation is complex, this approach can lead to slower performance due to the repeated accesses to `elements[i]`.
* This method assumes that the array is fixed-size and doesn't account for potential changes or null values.

**Other considerations**

* The use of `document.all` as a placeholder element may introduce additional overhead due to its dynamic nature.
* Modern JavaScript engines (e.g., V8, SpiderMonkey) have optimized garbage collection algorithms to minimize memory allocation and deallocation, reducing the impact of push-based approach on performance.

**Library usage**

There is no explicit library mentioned in the provided benchmarking test cases. However, the use of `document.all` implies that the code might be targeting older browsers or environments where `document.querySelector` or other DOM query methods are not available.

If any special JS features or syntax are used, it's not explicitly mentioned in this case.

Related benchmarks:

push vs index123 (version: 0)

Comparing performance of: Array.push vs Array[index]

Created: 3 years ago by: Guest

Jump to the latest result

Array.push

Array[index]

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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