Benchmark: test fill loop of size 2 versus for loop of size 2

Tests:

a
let a = Array(2).fill(0).map( (x, i) => i);
b
let a = []; a[0] = 0; for(let i = 0; i < 2; i++) { a[i] = i; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
a
b

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark definition and test cases.

**Benchmark Definition**
The benchmark definition is a JSON object that describes the test case. It has two main components:

1. **Script Preparation Code**: This section provides the JavaScript code that is executed before running the benchmark. In this case, it's empty.
2. **Html Preparation Code**: This section provides the HTML code that is used to prepare the environment for the benchmark. Again, it's empty.

**Test Cases**
There are two test cases:

1. **Case a**: The benchmark definition is `let a = Array(2).fill(0).map((x, i) => i);`. This creates an array of size 2 with the elements 0 and 1.
2. **Case b**: The benchmark definition is `let a = [];a[0] = 0; for(let i = 0; i < 2; i++) {a[i] = i;};`. This creates an empty array, adds an element to it (with value 0), and then uses a loop to add another element.

**What is tested?**
The benchmark tests the performance difference between two approaches:

1. **Array.prototype.fill()**: Case a uses `Array(2).fill(0).map((x, i) => i);`, which creates an array of size 2 using `Array.prototype.fill()` and then maps over it to transform each element.
2. **Manual loop assignment**: Case b uses a manual loop (`for(let i = 0; i < 2; i++)`) to add elements to the array.

**Pros and Cons**

1. **Array.prototype.fill()**:
	* Pros: concise, efficient, and easy to read.
	* Cons: may not be supported in older browsers or versions of JavaScript.
2. **Manual loop assignment**:
	* Pros: more control over the iteration process, potentially better performance in certain cases.
	* Cons: less concise and may be slower due to the overhead of the loop.

**Library usage**
There is no explicit library mentioned in the benchmark definition. However, `Array.prototype.fill()` uses a method from the ECMAScript standard (a specification that defines the behavior of JavaScript).

**Special JS feature or syntax**
There are no special features or syntax used in these test cases.

**Other alternatives**

* Other approaches to create arrays with two elements could be:
	+ Using a constructor function: `let a = new Array(2)`.
	+ Using a factory function: `(function(a, b){return a,b;})(0,1)`.
* Alternative loop constructs for adding elements to an array could include:
	+ For...of loop: `for (const element of a) {a.push(element);}`.
	+ Recursion.

It's worth noting that these alternatives may not affect performance in all scenarios, and the choice of approach ultimately depends on the specific requirements and constraints of your project.

Related benchmarks:

test fill loop of size 2 versus for loop of size 2 (version: 0)

Comparing performance of: a vs b

Created: 4 years ago by: Guest

Jump to the latest result

a

b

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):