Benchmark: array reassign vs array.splice

Tests:

assign
function assign() { let i = [ '1', '2', '3', '4', '5', '6', '7', '8', '9', '10', ]; let p = i.length; i = []; return i; } assign();
splice
function splice() { let i = [ '1', '2', '3', '4', '5', '6', '7', '8', '9', '10', ]; let p = i.length; i.splice(0, p); return i; } splice();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
assign
splice

Fastest: N/A

Slowest: N/A

Latest run results:

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

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**Overview**

The provided JSON represents a benchmark test case on MeasureThat.net, which compares the performance of two approaches: reassigning an array and using `Array.splice()` to reset its length.

**Benchmark Definition**

The benchmark is defined in JavaScript code, which consists of two functions:

1. `assign()`: This function creates an array with 10 elements, stores its length in a variable `p`, and then reassigned the array to an empty array.
2. `splice()`: This function creates an array with 10 elements, stores its length in a variable `p`, and then uses `Array.splice()` to remove all elements from the array.

**Options Compared**

The two options being compared are:

1. **Reassigning an array**: This approach involves creating a new reference to the original array by reassigning it to an empty array.
2. **Using `Array.splice()`**: This approach involves removing all elements from the array using `Array.splice()`, which modifies the original array.

**Pros and Cons of Each Approach**

1. **Reassigning an array**:
	* Pros:
		+ Creates a new reference to the original array, which can lead to better performance since it doesn't modify the original array.
		+ Can be more predictable and easier to understand for some developers.
	* Cons:
		+ Creates a new object in memory, which can lead to increased memory usage.
		+ May not work as expected if the original array is being used elsewhere in the code.
2. **Using `Array.splice()`**:
	* Pros:
		+ Modifies the original array in-place, which can lead to better performance since it doesn't create a new object.
		+ Can be more efficient when working with large arrays.
	* Cons:
		+ Modifies the original array, which can lead to unexpected behavior if the array is being used elsewhere in the code.
		+ May not work as expected for certain use cases (e.g., when using `Array.splice()` on a non-array object).

**Library and Special JavaScript Features**

There are no libraries mentioned in the provided benchmark definition.

**Special JavaScript Feature/Syntax**

None of the test cases use any special JavaScript features or syntax that requires explanation. However, it's worth noting that some browsers may have optimized performance for `Array.splice()` due to its widespread use in browser code.

**Other Alternatives**

If you need to reset an array's length without using either of these approaches, you can also consider:

1. Using `Array.fill(0)` or `Array.from(new Array(10).fill(0))` to create a new array filled with zeros.
2. Using `Array.prototype.length = 0;` to set the length of the array to zero.

However, these alternatives may not be as efficient or readable as using `reassign()` or `Array.splice()`, and should be used judiciously in production code.

Related benchmarks:

array reassign vs array.splice (version: 0)

array reassign vs array.splice

Comparing performance of: assign vs splice

Created: 3 years ago by: Guest

Jump to the latest result

assign

splice

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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