Benchmark: empty an array in JavaScript?(Yorkie)1

Tests:

Just instantiate new array
for (var e = 0; e < 100000; e++){ let size = 100; let arr1 = []; for (var i = 0; i < size; i++){ arr1.push(i); } arr1 = []; }
Set length to zero
for (var e = 0; e < 100000; e++){ let size = 100; let arr2 = []; for (var i = 0; i < size; i++){ arr2.push(i); } arr2.length = 0; }
Splice
for (var e = 0; e < 100000; e++){ let size = 100; let arr3 = []; for (var i = 0; i < size; i++){ arr3.push(i); } arr3.splice(0, arr3.length); }
Pop all values
for (var e = 0; e < 100000; e++){ let size = 100; let arr4 = []; for (var i = 0; i < size; i++){ arr4.push(i); } while(arr4.length > 0){ arr4.pop(); } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Just instantiate new array
Set length to zero
Splice
Pop all values

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Description**
The benchmark is designed to measure the performance of three different approaches for emptying an array in JavaScript:

1. Instantiating a new, empty array (`let arr = []`)
2. Setting the length of an existing array to zero (`arr.length = 0`)
3. Using `splice(0, arr.length)` to remove all elements from an array
4. Popping all elements from an array using a while loop (`while(arr.length > 0) { arr.pop(); }`)

**Options Comparison**

The benchmark compares the performance of these four approaches on a large array of size 100,000 elements.

* **Pros and Cons:**
	+ Instantiating a new array:
		- Pros: Simple, efficient, and creates a fresh copy of the array.
		- Cons: Can be slower than other methods if the array is very large or sparse.
	+ Setting length to zero:
		- Pros: Fast, as it only updates the internal reference count of the array.
		- Cons: May trigger garbage collection, which can slow down performance.
	+ Splice:
		- Pros: Can be faster than setting length to zero for large arrays with many elements.
		- Cons: Creates a new array object and may trigger garbage collection.
	+ Popping all values:
		- Pros: Simple and easy to implement.
		- Cons: May not be the most efficient approach, as it uses more iterations than other methods.

**Library Usage**
None of the benchmark definitions use any external libraries or frameworks. The focus is solely on measuring the performance of built-in JavaScript features.

**Special JS Features/Syntax**
The benchmark definition `splice(0, arr.length)` uses the `splice()` method with two arguments: the starting index (0) and the number of elements to remove (`arr.length`). This syntax is a shorthand way to remove all elements from an array.

**Other Alternatives**

If you want to test alternative approaches for emptying an array in JavaScript, some other options include:

* Using `Array.prototype.fill(0)` or `Array.from(new Array(size).fill(0))` to create a new array with all elements set to 0.
* Using `let arr = new Int32Array(size);` and then setting all elements to 0 using `arr.fill(0)`.
* Using a custom implementation, such as a loop that iterates over the array and assigns each element to a variable.

Keep in mind that these alternatives may have different performance characteristics depending on the specific use case and browser version.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:89.0) Gecko/20100101 Firefox/89.0

Browser/OS: Firefox 89 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Just instantiate new array	13.5 Ops/sec
Set length to zero	10.3 Ops/sec
Splice	11.6 Ops/sec
Pop all values	9.1 Ops/sec

Related benchmarks:

empty an array in JavaScript?(Yorkie)1 (version: 0)

Based on question on http://stackoverflow.com/questions/1232040/how-do-i-empty-an-array-in-javascript

Comparing performance of: Just instantiate new array vs Set length to zero vs Splice vs Pop all values

Created: 3 years ago by: Guest

Jump to the latest result

Just instantiate new array

Set length to zero

Splice

Pop all values

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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