Benchmark: Array.push(x) vs array[n]=x

Script Preparation code:

var LEN = 10000;
var arr = [];

Tests:

Array.push(x)
for (var x = 0; x < LEN; x++) arr.push(x);
array[n]=x
for (var x = 0; x < LEN; x++) arr[x] = x;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.push(x)
array[n]=x

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.6 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 17 on iOS 17.6

View result in a separate tab

Test name	Executions per second
Array.push(x)	1117.9 Ops/sec
array[n]=x	1176.5 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 benchmark and explain what is tested, compared options, pros and cons, and other considerations.

**Benchmark Definition**

The benchmark definition json provides two test cases:

1. `Array.push(x)`
2. `array[n]=x`

These two approaches are being compared to measure their performance difference in JavaScript.

**Options Compared**

In this benchmark, we have two main options:

a. **`arr.push(x)`**: This approach involves using the `push()` method of an array to add elements to it. The `push()` method takes one or more arguments and adds them to the end of the array.

b. **`arr[x] = x`**: This approach involves accessing an element at a specific index (`x`) in an array and assigning a value to it using the assignment operator (`=`).

**Pros and Cons**

a. **`arr.push(x)`**:

Pros:

* Easier to read and write, as it clearly conveys the intention of adding elements to an array.
* Less prone to errors, as the `push()` method is a standard part of the JavaScript API.

Cons:

* May be slower due to the overhead of creating a new element object and appending it to the end of the array.

b. **`arr[x] = x`**:

Pros:

* Faster, as accessing an existing element at a specific index is typically faster than adding a new element using `push()`.

Cons:

* More prone to errors, as incorrect indexing or assignment can lead to unexpected behavior.
* Less readable and maintainable, especially for large arrays or complex logic.

**Library Used**

There is no library explicitly mentioned in the benchmark definition. However, it's worth noting that the use of `arr` and `push()` suggests that this benchmark may be targeting modern JavaScript engines, which have optimized array operations.

**Special JS Features/ Syntax (None)**

There are no special features or syntax used in this benchmark.

**Benchmark Preparation Code**

The script preparation code provided is:
```javascript
var LEN = 10000;
var arr = [];
```
This initializes a variable `LEN` with the value `10000` and an empty array `arr`.

**Html Preparation Code**

The html preparation code is not provided, suggesting that this benchmark may be focusing on JavaScript performance rather than HTML-related aspects.

**Other Alternatives**

Some alternative approaches to comparing these two options might include:

* Using a more extensive array size or number of iterations
* Exploring different data types (e.g., objects, sets) for comparison
* Investigating the performance impact of using `push()` versus `assign()` methods on specific use cases (e.g., sorting, filtering)
* Comparing these approaches to other allocation mechanisms, such as `Object.create()` or `Array.prototype.fill()`

Keep in mind that the scope and focus of a benchmark can greatly influence its design and approach. This explanation provides a general understanding of the options compared and pros/cons for each approach.

Related benchmarks:

Array.push(x) vs array[n]=x (version: 0)

Comparing performance of: Array.push(x) vs array[n]=x

Created: one year ago by: Registered User

Jump to the latest result

Array.push(x)

array[n]=x

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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