Benchmark: Test slice vs splice

Script Preparation code:

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

Tests:

slice
list.push('slice'); list = list.slice(50000);
splice
list.push('splice'); list.splice(0, 50000);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
splice

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

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Let's dive into the details of this benchmark test.

**What is being tested?**

The test case compares the performance of two JavaScript methods:

1. `slice()`
2. `splice()` (with `shift()`)

These methods are used to manipulate arrays in JavaScript.

**Description of options compared:**

The two test cases compare the execution speed of manipulating a large array (100,000 elements) using the following approaches:

* **`slice()`**: This method creates a new array containing a subset of the original array's elements. In this case, it's used to remove the first 50,000 elements from the list.
* **`splice()` with `shift()`**: This combination is used to remove the first 50,000 elements from the list by shifting all elements after that index down.

**Pros and Cons of each approach:**

* **`slice()`**:
	+ Pros: Creates a new array without modifying the original one.
	+ Cons: Creates a copy of the entire subset, which can be memory-intensive for large arrays.
	+ Performance impact: This method is slower because it creates a new array.
* **`splice()` with `shift()`**:
	+ Pros: Modifies the original array in place, reducing memory usage.
	+ Cons: Mutates the original array, potentially affecting other parts of the code that rely on its integrity.

**Other considerations:**

When choosing between these methods, consider the following:

* If you need to preserve the original array's structure and do not mind creating a new copy for performance reasons, `slice()` might be a better choice.
* If memory efficiency is crucial, or you're modifying the original array anyway, using `splice()` with `shift()` can be a more lightweight solution.

**Library and special JS feature usage:**

No external libraries are used in this benchmark. The JavaScript features demonstrated are built-in:

* `slice()`: A method that creates a new array containing a subset of elements from an existing array.
* `splice()`: A method that removes or inserts elements at specific indices in an array.

**Other alternatives:**

For similar use cases, consider these alternatives:

* Using `Array.prototype.filter()` to create a new array with elements meeting certain conditions. While not exactly the same as `slice()`, it's another way to manipulate arrays.
* Implementing custom algorithms using loops or recursive functions for more complex data structures.

Keep in mind that the choice between these methods depends on specific requirements, such as performance needs, memory constraints, and desired behavior (mutation vs. preservation of original array).

Related benchmarks:

Test slice vs splice (version: 0)

100k list splice and shift win, they mutate list slice loose, it creates a copy of list 7.5x slower

Comparing performance of: slice vs splice

Created: 3 years ago by: Guest

Jump to the latest result

slice

splice

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):