Benchmark: slice-splice - MeasureThat.net

Script Preparation code:

var arr1 = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];

Tests:

splice
let arr2 = arr1.splice(5);
slice
arr1.splice(0, 6);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
splice
slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is a fascinating topic, and analyzing the provided benchmark can provide valuable insights into the trade-offs of different approaches.

**What's being tested?**

The benchmark measures the performance of two common array manipulation operations in JavaScript: `slice` and `splice`. The test cases are:

1. `slice`: Removing the first 6 elements from an array using `arr1.splice(0, 6);`.
2. `splice`: Removing a single element at index 5 from the same array using `arr1.splice(5);`.

**Options compared**

In this benchmark, two options are being compared:

1. **`slice`**: This method returns a shallow copy of a portion of an array and leaves the original array unchanged.
2. **`splice`**: This method modifies the original array by removing or replacing elements.

**Pros and Cons**

### `slice`

Pros:

* Fast: `slice` is generally faster than `splice` because it doesn't modify the original array.
* Efficient memory usage: `slice` creates a new array with the desired elements, which can be more efficient than modifying the original array using `splice`.

Cons:

* Returns a new array: If you need to perform operations on the modified array, `slice` returns a new array that needs to be processed separately.
* Creates an intermediate result: Depending on the use case, creating an intermediate result might lead to additional memory allocation and garbage collection.

### `splice`

Pros:

* Modifies the original array in place: If you need to perform operations on the modified array, `splice` returns a new array only if you're not using the returned value (i.e., you assign it to another variable).
* Avoids creating an intermediate result: By modifying the original array, `splice` avoids creating additional memory allocation and garbage collection.

Cons:

* Slower: `splice` is generally slower than `slice` because it modifies the original array.
* Less efficient memory usage: `splice` can be less efficient in terms of memory usage if the modified array needs to be stored for a longer time.

**Other considerations**

When choosing between `slice` and `splice`, consider the following:

* If you need to perform operations on the modified array, use `splice`. Otherwise, `slice` might be a better choice.
* If you're working with large arrays, `slice` might be more efficient due to its faster execution time.

**Library and special JS features**

There are no libraries mentioned in this benchmark. However, if you notice any unusual behavior or optimizations, it's possible that the developer used a specific library or JavaScript feature like:

* `Array.prototype.slice.call()`: This method is used instead of `arr1.slice(5)`. It's equivalent but might be used for performance reasons.
* `bind()` or `call()`: These methods are sometimes used to optimize array operations, but they're not necessary in this specific benchmark.

**Alternative approaches**

If you want to measure the performance of other array manipulation operations, consider adding test cases for:

* `concat()`: Concatenating two arrays using `arr1.concat(arr2)` or `arr1.concat([5, 6, 7])`.
* `set():` Adding elements to an existing array using `arr1.set(index, value)`, which is still experimental and not widely supported.

You can also explore measuring the performance of different data structures, such as arrays with a fixed length or objects, or compare the performance of various JavaScript engines like V8 (used by Google Chrome), SpiderMonkey (used by Mozilla Firefox), and others.

Related benchmarks:

slice-splice (version: 0)

Comparing performance of: splice vs slice

Created: 6 years ago by: Guest

Jump to the latest result

splice

slice

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):