Benchmark: Array with and without predefined sizes

Tests:

Array predefined size
const arr = Array(10000); for (let i = 0; i < 10000; i++) { arr[i] = i * 2; }
Array no size
const arr = []; for (let i = 0; i < 10000; i++) { arr[i] = i * 2; }
array no size (push)
const arr = []; for (let i = 0; i < 10000; i++) { arr.push(i * 2); }
Array predefined size (large)
const arr = Array(1000000); for (let i = 0; i < 1000000; i++) { arr[i] = i * 2; }
Array no size (large)
const arr = []; for (let i = 0; i < 1000000; i++) { arr[i] = i * 2; }
Array predefined size (small)
const arr = Array(100); for (let i = 0; i < 100; i++) { arr[i] = i * 2; }
Array no size (small)
const arr = []; for (let i = 0; i < 100; i++) { arr[i] = i * 2; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array predefined size
Array no size
array no size (push)
Array predefined size (large)
Array no size (large)
Array predefined size (small)
Array no size (small)

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript benchmarks and explain what's being tested, compared, and the pros/cons of each approach.

**Benchmark Overview**

The benchmark measures the performance of creating arrays with different sizes using two approaches: assigning elements to an existing array or adding elements to an empty array. The test cases cover four scenarios:

1. Predefined size (small)
2. No predefined size
3. Array push method
4. Large array

**Options Compared**

The benchmark compares the performance of three options:

1. **Assignment**: Creating a new array and assigning elements using the syntax `arr[i] = i * 2;`.
2. **Push**: Creating an empty array and adding elements using the `push()` method: `arr.push(i * 2);`.
3. **No Array Creation**: Using the `Array` constructor with no size, which creates a small array (only 1 element) by default.

**Pros/Cons of Each Approach**

1. **Assignment**:
	* Pros: Simple and familiar syntax for most developers.
	* Cons: Creates a new array, which can be memory-intensive and slow for large arrays.
2. **Push**:
	* Pros: More efficient than assignment for large arrays since it only adds elements to an existing array without creating a new one.
	* Cons: Requires an empty array, and the push method can be slower due to its internal implementation.
3. **No Array Creation**:
	* Pros: No memory allocation or overhead, making it potentially faster for small arrays.
	* Cons: Creates a small array (only 1 element) by default, which may not accurately represent real-world scenarios.

**Library and Special JS Feature**

The benchmark does not use any libraries beyond the built-in `Array` constructor. There are no special JavaScript features mentioned, so we can assume that only standard JavaScript syntax is used.

**Other Alternatives**

If you wanted to explore alternative approaches, consider the following:

1. **Splice**: Instead of push, you could use `arr.splice(i, 0, i * 2);` to add elements at a specific position.
2. **Array.fill()**: Fill an array with a value using `arr.fill(0, i, 10000)`.
3. **Typed Arrays**: Consider using typed arrays (e.g., Int8Array or Float64Array) for optimized performance and memory usage.

Keep in mind that these alternatives might not be directly comparable to the original benchmark, as they may have different use cases and performance characteristics.

By understanding what's being tested and compared, you can better analyze the results and decide which approach is most suitable for your specific use case.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36

Browser/OS: Chrome 106 on Linux

View result in a separate tab

Test name	Executions per second
Array predefined size	73014.6 Ops/sec
Array no size	26950.1 Ops/sec
array no size (push)	24307.5 Ops/sec
Array predefined size (large)	377.5 Ops/sec
Array no size (large)	81.1 Ops/sec
Array predefined size (small)	3219834.8 Ops/sec
Array no size (small)	2131437.2 Ops/sec

Related benchmarks:

Array with and without predefined sizes (version: 0)

Comparing performance of: Array predefined size vs Array no size vs array no size (push) vs Array predefined size (large) vs Array no size (large) vs Array predefined size (small) vs Array no size (small)

Created: 2 years ago by: Guest

Jump to the latest result

Array predefined size

Array no size

array no size (push)

Array predefined size (large)

Array no size (large)

Array predefined size (small)

Array no size (small)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):