Benchmark: Splice vs Shift perf

Script Preparation code:

var array = [1, 2, 3, 4, 5, 6, 7, 8]
var itemsToRemove = 1

Tests:

array.splice()
array.splice(0, itemsToRemove)
array.shift()
array.shift()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.splice()
array.shift()

Fastest: N/A

Slowest: N/A

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/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
array.splice()	16827838.0 Ops/sec
array.shift()	34394256.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON benchmark definitions and explain what's being tested, compared, and analyzed.

**What is being tested?**

The benchmark tests two JavaScript methods: `array.splice()` and `array.shift()`. These methods are used to remove elements from an array. The test aims to compare the performance of these two methods.

**Options compared:**

Two options are being compared:

1. **`array.splice(0, itemsToRemove)`**: This method removes the specified number of elements from the beginning of the array. The `itemsToRemove` variable is set to 1.
2. **`array.shift()`**: This method removes and returns the first element from the array.

**Pros and Cons:**

Both methods have their advantages and disadvantages:

*   **`array.splice(0, itemsToRemove)`**:
    *   Pros:
        *   More control over the number of elements removed.
        *   Can be used to remove elements at any position in the array.
    *   Cons:
        *   Requires more CPU cycles due to the overhead of creating a new array with the remaining elements.
*   **`array.shift()`**:
    *   Pros:
        *   Faster and more lightweight, as it only requires removing the first element from the array.
        *   Simpler code and easier to read.
    *   Cons:
        *   Less control over the number of elements removed.

**Other considerations:**

The test does not consider other factors that might affect performance, such as:

*   The size of the array (i.e., the number of elements).
*   The type of data stored in the array (e.g., numbers vs. objects).

**Library and its purpose:**

In the benchmark preparation code, a simple JavaScript array is created using `var array = [1, 2, 3, 4, 5, 6, 7, 8]`. The `itemsToRemove` variable is set to 1. This creates an array with 8 elements.

**Special JS feature or syntax:**

There are no special features or syntax used in this benchmark.

**Alternatives:**

Other alternatives for removing elements from an array include:

*   Using the `filter()` method to create a new array with only the desired elements.
*   Using the `map()` method to create a new array with modified versions of the elements.
*   Using a loop to manually remove and store the removed elements in a separate array.

However, for most cases, using `array.splice()` or `array.shift()` is more efficient and straightforward.

Related benchmarks:

Splice vs Shift perf (version: 0)

Comparing performance of: array.splice() vs array.shift()

Created: 2 years ago by: Guest

Jump to the latest result

array.splice()

array.shift()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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