Benchmark: array.fill VS array.push

Tests:

array.push
const array = []; const n = 100000; for (let i = 0; i < n; i++) { array.push('#123456'); }
array.fill
const n = 100000; const array = Array(n).fill('#123456');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.push
array.fill

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
array.push	5747.1 Ops/sec
array.fill	12402.9 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 explain the JavaScript benchmark you provided.

**What is being tested?**

The two test cases are comparing the performance of two different ways to fill an array with a large number of elements: using the `fill()` method versus pushing individual elements onto the array using the `push()` method. The goal is to determine which approach is faster and more efficient for filling large arrays.

**Options compared:**

There are only two options being tested:

1. **`array.fill()`**: This method fills all elements of an array with a specified value.
2. **`array.push()```**: This method adds one or more elements to the end of an array and returns the new length of the array.

**Pros and Cons:**

* `array.fill()`: Pros:
	+ Faster, as it only requires a single operation to fill all elements.
	+ More efficient in terms of memory usage, as it doesn't require creating a large number of intermediate elements.
	Cons:
	+ Limited flexibility, as the entire array is filled with the same value.
* `array.push()`: Pros:
	+ More flexible, as each element can be different.
	+ Can be useful when working with dynamic data or arrays that need to be modified frequently.
Cons:
	+ Slower, as it requires a separate operation for each element.
	+ Less efficient in terms of memory usage, as it creates intermediate elements.

**Library and purpose:**

There is no explicit library mentioned in the benchmark definition. However, `Array.prototype.fill()` is a standard method provided by the JavaScript array prototype, which allows you to fill an array with a specified value.

**Special JS feature or syntax:**

The test case doesn't explicitly mention any special JavaScript features or syntax, but it does rely on modern JavaScript features like arrow functions (`=>`) and template literals (`\r\n`).

**Other considerations:**

* The benchmark is designed to measure the performance of filling large arrays, which may not be a common use case in everyday programming.
* The test results are likely biased towards modern browsers, as they tend to optimize for performance and efficiency.

**Alternative approaches:**

Other alternative approaches to filling an array could include:

1. Using `Array.prototype.splice()`: This method allows you to remove or add elements to an array at a specified index, which can be useful in certain situations.
2. Using a library like `lodash`'s `fill()` function: This function provides more flexibility and customization options compared to the built-in `Array.prototype.fill()` method.
3. Using a loop with `new Array(n).map()`: This approach uses the `map()` method to create a new array filled with elements, which can be useful when working with dynamic data.

Keep in mind that these alternative approaches may have different performance characteristics and trade-offs compared to the original benchmark test.

Related benchmarks:

array.fill VS array.push (version: 0)

Comparing performance of: array.push vs array.fill

Created: 2 years ago by: Registered User

Jump to the latest result

array.push

array.fill

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):