Benchmark: array.splice vs for loop for arrays

Script Preparation code:

s = [];
for (var i=0; i < 1000; i++) s.push(i*i);

Tests:

array.splice
const a = []; a.splice(0, a.length, ...s);
puhs in for loop
const a = []; for (var x of s) a.push(x);
array.splice w/o spread
const a = []; a.splice.apply(a, [0, 0].concat(s));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.splice
puhs in for loop
array.splice w/o spread

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 115 on Android

View result in a separate tab

Test name	Executions per second
array.splice	169100.8 Ops/sec
puhs in for loop	137453.9 Ops/sec
array.splice w/o spread	157720.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what is being tested.

**Benchmark Definition**

The website, MeasureThat.net, provides a JSON object that defines a microbenchmark. The benchmark tests two approaches for inserting elements into an array:

1. `array.splice`
2. `push` in a `for` loop

Here's a brief explanation of each approach:

* `array.splice`: This method replaces a portion of the array with new values. In this case, it removes the first element of the array (length 0) and then inserts all elements from the `s` array into the resulting array.
* `push` in a `for` loop: This method iterates over each element in the `s` array and adds it to the end of the `a` array.

**Library: none**

There is no external library being used in this benchmark. The implementation relies solely on built-in JavaScript functions.

**Special JS features/syntax: none**

This benchmark does not utilize any special JavaScript features or syntax.

Now, let's discuss the pros and cons of each approach:

1. `array.splice`:
	* Pros:
		+ Can be more efficient for large arrays since it modifies the array in place.
		+ Can reduce memory allocation and garbage collection overhead.
	* Cons:
		+ Can be slower for small arrays due to the additional overhead of modifying the array.
		+ May not be suitable for use cases where preserving the original order of elements is crucial.
2. `push` in a `for` loop:
	* Pros:
		+ Simple and easy to understand implementation.
		+ Preserves the original order of elements.
	* Cons:
		+ Can be less efficient for large arrays since it creates new intermediate arrays during each iteration.

**Alternatives**

Some alternative approaches could include:

1. Using `Array.prototype.concat()` instead of `push` in a `for` loop: This method combines two or more arrays into a single array and can be faster than the `push` approach.
2. Using `array.map()` instead of `splice`: This method applies a function to each element of an array and returns a new array with the results. It can be more efficient for large arrays but may not preserve the original order of elements.

In summary, the benchmark tests two approaches for inserting elements into an array: `array.splice` and `push` in a `for` loop. The choice between these approaches depends on factors such as performance requirements, memory constraints, and preservation of element order.

Related benchmarks:

array.splice vs for loop for arrays (version: 0)

Comparing performance of: array.splice vs puhs in for loop vs array.splice w/o spread

Created: one year ago by: Guest

Jump to the latest result

array.splice

puhs in for loop

array.splice w/o spread

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):