Benchmark: Add new element to large array (preperation): push vs destructuring vs bracket access

Script Preparation code:

var params = [ "hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true,"hello", true, 7 ]

Tests:

spread operator
var other = [ ...params, 'new' ]
Push
params.push('new');
bracket access
params[ params.length ] = 'new';

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread operator
Push
bracket access

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what's being tested, compared, and considered in each test case.

**Benchmark Definition**

The benchmark is testing three different approaches to adding a new element to a large array:

1. **Push**: Using the `push()` method to add an element to the end of the array.
2. **Destructuring**: Using the spread operator (`...`) to create a new array with the existing elements and the new one appended.
3. **Bracket access**: Accessing the last index of the array using bracket notation (`params[ params.length ] = 'new'`).

**Options Compared**

The three approaches are compared in terms of performance, specifically:

* Execution time (measured in executions per second)
* Browser-specific optimizations and cache effects

**Pros and Cons of Each Approach**

1. **Push**:
	* Pros: Fast and efficient, as it doesn't require creating a new array.
	* Cons: May cause issues if the array is large and the `push()` method has to traverse the entire array to find the correct index.
2. **Destructuring (Spread Operator)**:
	* Pros: Creates a new array with a clear separation between existing elements and the new one, making it easier to debug.
	* Cons: May be slower than `push()` due to the overhead of creating a new array.
3. **Bracket access**:
	* Pros: Simple and concise, as it directly accesses the last index of the array.
	* Cons: May cause issues if the array is large or has many elements, as it requires calculating the index manually.

**Library Used**

The `push()` method uses the JavaScript built-in `Array.prototype.push()` method. No specific library is required for this test case.

**Special JS Feature/Syntax**

None mentioned in the provided code.

**Benchmark Preparation Code**

The preparation code creates a large array `params` with 20 elements, including some strings and booleans, and then defines a new variable `other` to hold the modified array. The code is:
```javascript
var params = [ "hello", true, "hello", true, ...params, 'new' ];
```
This creates a copy of the original `params` array using destructuring, appends the new element `'new'`, and assigns it to the new variable `other`.

**Individual Test Cases**

Each test case defines a different variant of the benchmark:

1. **Spread operator**: Uses the spread operator (`...`) to create a new array with the existing elements and the new one appended.
```javascript
var other = [ ...params, 'new' ];
```
2. **Push**: Uses the `push()` method to add an element to the end of the array.
```javascript
params.push('new');
```
3. **Bracket access**: Accesses the last index of the array using bracket notation (`params[ params.length ] = 'new'`).
```javascript
params[ params.length ] = 'new';
```
**Latest Benchmark Result**

The latest benchmark result shows the execution time for each test case on a desktop Firefox 105 browser:

1. **Push**: 21885012 executions per second
2. **Bracket access**: 16182047 executions per second
3. **Spread operator**: 562220.875 executions per second

These results suggest that `push()` is the fastest approach, followed by bracket access, and then destructuring (spread operator).

Related benchmarks:

Add new element to large array (preperation): push vs destructuring vs bracket access (version: 0)

Comparing performance of: spread operator vs Push vs bracket access

Created: 3 years ago by: Guest

Jump to the latest result

spread operator

Push

bracket access

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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