Benchmark: Array population test

Script Preparation code:

var arraySize = 10000;
var iterations = arraySize + 100;
var data;
var operate = function(){
  for(var index = 0; index < iterations; index++){
    if(data.length == arraySize) data.pop(); 
    data.unshift({});
    
  }
}

Tests:

new Array
data = new Array(arraySize); operate();
brackets
data = []; operate();
brackets with length
data = []; data.length=arraySize; operate();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Array
brackets
brackets with length

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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 JSON**

The benchmark definition JSON provides information about the test case, including:

* **Name**: "Array population test"
* **Description**: None
* **Script Preparation Code**: This code is executed before running the benchmark. It sets up variables for the array size and iterations, as well as a function `operate()`. The purpose of this function is to populate an array with empty objects.
* **Html Preparation Code**: None

**Test Cases**

The test cases are defined in the following JSON:

```json
[
    {
        "Benchmark Definition": "data = new Array(arraySize);\r\noperate();",
        "Test Name": "new Array"
    },
    {
        "Benchmark Definition": "data = [];\r\noperate();",
        "Test Name": "brackets"
    },
    {
        "Benchmark Definition": "data = [];\r\ndata.length=arraySize;\r\noperate();",
        "Test Name": "brackets with length"
    }
]
```

These test cases compare three different ways of creating an array in JavaScript:

1. **new Array**: Creates a new, empty array using the `new` keyword.
2. **[]**: Creates a new, empty array using square brackets (`[]`).
3. **Array constructor with length assignment**: Assigns a value to the `length` property of an object that will be used as an array.

**Options Compared**

The three test cases compare different ways of creating an array, which has implications for performance and code readability.

* **Pros and Cons:**
	+ `new Array`: Creates a new, empty array. Pros: more explicit creation, can be faster. Cons: requires more memory.
	+ `[]`: Creates a new, empty array using square brackets. Pros: concise syntax, often preferred by developers. Cons: may be slower due to the need for extra processing.
	+ `Array constructor with length assignment**: Assigns a value to the `length` property of an object that will be used as an array. Pros: can be faster and more memory-efficient than the other two options. Cons: requires explicit memory management, which can add complexity.
* **Other Considerations:**
	+ The use of `new Array` or `[]` may also affect how JavaScript engines optimize array creation. Some engines may create arrays using a different allocation strategy that takes into account the type and size of the array.

**Library Used**

None of the test cases explicitly uses any external libraries.

**Special JS Features/Syntax**

None, except for the use of `const` in some parts of the benchmark definition code (e.g., `"var data;"` is not present in the test cases).

**Alternatives**

Other alternatives to measure array creation performance might include:

* Using a different language or implementation that has optimized array creation.
* Implementing a custom microbenchmarking framework that allows for more fine-grained control over benchmarking scenarios.
* Running multiple benchmarks with varying input sizes and array lengths.

Keep in mind that MeasureThat.net's focus is on comparing JavaScript engine performance, so alternatives might be less relevant to the specific use case.

Related benchmarks:

Array population test (version: 0)

Comparing performance of: new Array vs brackets vs brackets with length

Created: 9 years ago by: Guest

Jump to the latest result

new Array

brackets

brackets with length

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):