Benchmark: splice vs slice split array into two

Script Preparation code:

var arr = [...Array(1000)].map((_, index) => `item-${index}`);
var SPLIT_LENGTH = 555;

Tests:

slice
var a = arr.slice(0, SPLIT_LENGTH); var b = arr.slice(SPLIT_LENGTH); console.log(a.length, b.length);
splice
var a = arr; var b = a.splice(SPLIT_LENGTH, a.length - SPLIT_LENGTH); console.log(a.length, b.length);

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:

No previous run results

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

LLMs can make mistakes. Check important info.

Let's dive into the world of MeasureThat.net and analyze the provided benchmark.

**Benchmark Definition**

The benchmark definition is a JSON object that contains information about the test case. In this case, there are two benchmark definitions:

1. `splice vs slice split array into two`
2. `var a = arr.slice(0, SPLIT_LENGTH); var b = arr.slice(SPLIT_LENGTH); console.log(a.length, b.length)`
3. `var a = arr; var b = a.splice(SPLIT_LENGTH, a.length - SPLIT_LENGTH); console.log(a.length, b.length)`

The benchmark definition specifies the script preparation code, HTML preparation code (which is empty in this case), and a brief description of the test.

**Script Preparation Code**

In both cases, the script preparation code creates an array `arr` with 1000 elements, each labeled as "item-<index>". It also defines a variable `SPLIT_LENGTH` to specify the split point for the array.

```javascript
var arr = [...Array(1000)].map((_, index) => `item-${index}`);\r\nvar SPLIT_LENGTH = 555;
```

**Options Compared**

The benchmark compares two options:

1. **Slice**: Using the `slice()` method to create two arrays: one with elements up to `SPLIT_LENGTH` and another with elements from `SPLIT_LENGTH` to the end of the array.
2. **Splice**: Using the `splice()` method to remove elements from the original array `arr`, creating a new array with elements before `SPLIT_LENGTH` and another with elements after.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

### Slice

Pros:

* More explicit control over the split point
* Easier to understand the intent of the code
* Less overhead compared to `splice()`

Cons:

* May be slower due to the creation of two new arrays
* Requires manual indexing or offset calculation for subsequent operations

### Splice

Pros:

* Faster execution time, as only one array is modified
* Simplifies subsequent operations on the resulting array

Cons:

* Less explicit control over the split point
* Can lead to unexpected behavior if not used carefully (e.g., modifying the original array)

**Library**

There are no libraries mentioned in the benchmark definition. However, both `slice()` and `splice()` methods are built-in JavaScript methods.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax used in this benchmark. It uses standard JavaScript syntax for array manipulation and logging.

**Alternatives**

If you were to rewrite this benchmark using alternative approaches, you might consider:

* Using `Array.prototype.slice.call()` or `Array.prototype.splice.call()` to avoid the need for explicit array creation.
* Employing more advanced techniques, such as using a `Map` or `Set` data structure to achieve similar results with reduced overhead.
* Optimizing the benchmark by parallelizing execution across multiple cores or threads.

However, since MeasureThat.net is focused on measuring the performance of specific JavaScript operations, it's essential to use standard JavaScript methods and syntax to ensure accurate comparisons.

Related benchmarks:

splice vs slice split array into two (version: 0)

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 llama3.2:3b, generated one year ago):