Benchmark: empty a small array in JavaScript?

Tests:

Just instantiate new array
var size = 10; var arr1 = []; for (var i = 0; i < size; i++){ arr1.push(i); } arr1 = [];
Set length to zero
var size = 10; var arr2 = []; for (var i = 0; i < size; i++){ arr2.push(i); } arr2.length = 0;
Splice
var size = 10; var arr3 = []; for (var i = 0; i < size; i++){ arr3.push(i); } arr3.splice(0, arr3.length);
Pop all values
var size = 10; var 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 27 days ago):

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The MeasureThat.net website allows users to create and run JavaScript microbenchmarks, including the one described in the provided JSON data. The goal of this benchmark is to measure how quickly different approaches can empty a small array in JavaScript.

**Options Being Compared**

There are four options being compared:

1. **Just instantiate new array**: This option involves creating a new array with the same length as the original array, but without any elements.
2. **Set length to zero**: This option involves setting the length property of the array to 0, effectively emptying it.
3. **Splice**: This option uses the `splice` method to remove all elements from the array.
4. **Pop all values**: This option uses a loop with `pop` method to remove all elements from the array.

**Pros and Cons of Each Approach**

Here's a brief analysis of each approach:

1. **Just instantiate new array**:
	* Pros: Fastest, as it creates a new array without modifying the existing one.
	* Cons: Creates an unnecessary new array object.
2. **Set length to zero**:
	* Pros: Does not create any additional objects or arrays.
	* Cons: May be slower due to the need to update the `length` property of the array.
3. **Splice**:
	* Pros: Can be faster than setting the `length` property, as it modifies the existing array object.
	* Cons: Requires an additional method call and may cause unnecessary garbage collection.
4. **Pop all values**:
	* Pros: Uses a simple loop with built-in methods, which can be optimized by modern browsers.
	* Cons: May be slower than the other approaches due to the need for multiple `pop` method calls.

**Library and Special JS Features**

None of the test cases use any external libraries. However, they do utilize some special JavaScript features:

* **For loops**: Used in all test cases to create arrays with a large number of elements.
* **Array methods**: Such as `push`, `splice`, and `pop` are used in each test case.

**Other Considerations**

When writing performance-critical code, it's essential to consider the following factors:

* **Memory allocation and deallocation**: Creating new objects or arrays can be expensive due to memory allocation and garbage collection.
* **Method call overhead**: Excessive method calls can lead to slower performance.
* **Browser optimizations**: Modern browsers often optimize array operations, such as `splice` and `pop`, for better performance.

**Alternatives**

If you're interested in exploring alternative approaches or optimizing your own JavaScript code, consider the following alternatives:

* Use a library like Lodash or Ramda for array manipulation, which can provide faster and more concise solutions.
* Utilize modern browser features like WebAssembly or SIMD instructions to accelerate certain operations.
* Profile your code using tools like Chrome DevTools or Node.js Inspector to identify performance bottlenecks.

Keep in mind that the best approach will depend on your specific use case and requirements. MeasureThat.net's benchmark results can serve as a starting point for further optimization and experimentation.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36

Browser/OS: Chrome 107 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Just instantiate new array	52039660.0 Ops/sec
Set length to zero	23145296.0 Ops/sec
Splice	27681724.0 Ops/sec
Pop all values	35347952.0 Ops/sec

Related benchmarks:

empty a small array in JavaScript? (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: one year 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 27 days ago):