Benchmark: Array population test

Script Preparation code:

var size = 10000;

Tests:

new Array
var data = new Array(size); for(var index = 0; index < size; index++){ data.unshift({}); }
brackets
var data = []; for(var index = 0; index < size; index++){ data.unshift({}); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Array
brackets

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36

Browser/OS: Chrome 53 on Linux

View result in a separate tab

Test name	Executions per second
new Array	26.9 Ops/sec
brackets	68.9 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the benchmark and its results.

**Benchmark Overview**

The MeasureThat.net website allows users to create and run JavaScript microbenchmarks. The provided benchmark is designed to measure the performance of two different approaches for populating an array: using the `new Array` constructor and using square brackets (`[]`). The benchmark is set up to generate a large array with 10,000 elements, where each element is an empty object.

**Benchmark Definitions**

There are two individual test cases defined in the benchmark:

1. **"new Array"`**: This test case uses the `new Array` constructor to create an array and then uses the `unshift()` method to add 10,000 empty objects to the array.
2. **"brackets"`**: This test case uses square brackets (`[]`) to create an array-like object and then uses the `unshift()` method to add 10,000 empty objects to the array.

**Options Compared**

The two approaches compared in this benchmark are:

* Using the `new Array` constructor to create a traditional array
* Using square brackets (`[]`) to create an array-like object

**Pros and Cons of Each Approach**

1. **"new Array"`**:
	* Pros:
		+ Traditional arrays provide better performance and support for various methods like `indexOf()`, `slice()`, etc.
		+ Can be more memory-efficient for large datasets
	* Cons:
		+ May have slower performance compared to array-like objects
		+ May not be as flexible or forgiving with regards to method calls
2. **"brackets"`**:
	* Pros:
		+ Array-like objects can provide faster performance and better support for certain methods like `push()`, `pop()`, etc.
		+ Can be more memory-efficient in some cases (e.g., when using sparse arrays)
	* Cons:
		+ May not provide the same level of support for traditional array methods
		+ May require more careful handling to avoid issues with method calls and other edge cases

**Library Used**

There is no library explicitly mentioned in the benchmark. However, it's worth noting that both `new Array` and array-like objects use internal methods like `unshift()` and `push()` which are part of the JavaScript standard library.

**Special JS Features or Syntax**

There are no special features or syntax used in this benchmark that would require additional explanation.

**Other Alternatives**

Some other alternatives to using traditional arrays and array-like objects include:

* Using `Array.from()`: This method creates a new, shallow-copied array from an array-like object or an iterable.
* Using `Map` or `Set`: These built-in data structures provide efficient ways to store and manipulate key-value pairs or collections of values.
* Using libraries like Lodash or Underscore.js: These libraries provide utility functions for working with arrays, objects, and other data structures.

Keep in mind that the choice of approach depends on the specific requirements and use cases of your application.

Related benchmarks:

Array population test (version: 0)

Comparing performance of: new Array vs brackets

Created: 8 years ago by: Guest

Jump to the latest result

new Array

brackets

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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