Benchmark: fill array with value: map(callback) vs fill(value) 2

Tests:

.map(callback) - 1 000 elements
const result = Array.from({length:10000}, (_,i)=>i)
.fill(value) - 1 000 elements
const result = Array(10000).fill().map((a, i) => i);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.map(callback) - 1 000 elements
.fill(value) - 1 000 elements

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser/OS: Chrome 122 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
.map(callback) - 1 000 elements	3654.4 Ops/sec
.fill(value) - 1 000 elements	34224.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared, and the pros and cons of each approach.

**Benchmark Definition**

The benchmark definition represents a JavaScript microbenchmark that tests two different ways to fill an array with values: using the `.map()` method (callback) and using the `.fill()` method.

The benchmark is defined as:

```json
{
    "Name": "fill array with value: map(callback) vs fill(value) 2",
    "Description": null,
    "Script Preparation Code": null,
    "Html Preparation Code": null
}
```

This definition indicates that we are comparing two specific methods for filling an array, but the actual script preparation code and HTML preparation code are empty, suggesting that these are not part of the benchmark.

**Individual Test Cases**

The benchmark has two individual test cases:

```json
[
    {
        "Benchmark Definition": "const result = Array.from({length:10000}, (_,i)=>i)",
        "Test Name": ".map(callback) - 1 000 elements"
    },
    {
        "Benchmark Definition": "const result = Array(10000).fill().map((a, i) => i);",
        "Test Name": ".fill(value) - 1 000 elements "
    }
]
```

These test cases are comparing the performance of two different approaches to fill an array with values:

1. `.map(callback)` method
2. `.fill()` method

The first test case uses `Array.from()`, which is a modern JavaScript method for creating an array from an iterable, and it provides a callback function to transform each element.

The second test case uses the older `Array()` constructor to create an empty array, followed by the `.fill()` method to fill the array with values.

**Library Used**

There is no specific library mentioned in the benchmark definition or test cases. However, note that `Array.from()` is a built-in JavaScript method introduced in ECMAScript 2015 (ES6).

**Special JS Feature/Syntax**

None of the provided test cases use any special JavaScript features or syntax.

**Comparison and Pros/Cons**

The comparison between `.map(callback)` and `.fill(value)` methods can be summarized as follows:

* `.map(callback)`: This method is generally slower than `.fill()` because it iterates over each element in the array, applying the callback function to transform each value. This approach provides more flexibility but comes at a performance cost.
	+ Pros: Provides more control over the transformation process.
	+ Cons: Slower and may not be suitable for large datasets or high-performance applications.
* `.fill(value)`: This method is generally faster than `.map(callback)` because it simply assigns the provided value to each element in the array. This approach provides a simple, straightforward way to fill an array with values.
	+ Pros: Faster and more lightweight than `.map(callback)`.
	+ Cons: Less control over the transformation process.

**Other Alternatives**

If you need to perform complex transformations on large datasets, other alternatives to `.map(callback)` include:

* Using `Array.prototype.forEach()` method
* Utilizing third-party libraries like Lodash or Ramda for functional programming
* Leveraging modern JavaScript features like `for...of` loops or generators

Keep in mind that these alternatives may have varying performance characteristics compared to `.map(callback)`.

Related benchmarks:

fill array with value: map(callback) vs fill(value) 2 (version: 0)

Comparing performance of: .map(callback) - 1 000 elements vs .fill(value) - 1 000 elements

Created: 9 months ago by: Guest

Jump to the latest result

.map(callback) - 1 000 elements

.fill(value) - 1 000 elements

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):