Benchmark: non-mutating array remove: spread and slice vs slice and splice

Script Preparation code:

var array = Array.from({ length: 100 }).map((val, i) => i);

Tests:

spread
var output = [...array.slice(0, 38), ...array.slice(39)]
splice
var output = array.slice().splice(38, 1)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
splice

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.

Let's break down the benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is testing two different approaches to remove elements from an array:

1. `var output = [...array.slice(0, 38), ...array.slice(39)]` (spread operator)
2. `var output = array.slice().splice(38, 1)` (using the `splice()` method)

**Options Compared**

The benchmark is comparing two options for removing elements from an array:

* **Spread Operator**: Using the spread operator (`...`) to create a new array with the desired elements.
* **Splice Method**: Using the `splice()` method to remove elements from the original array.

**Pros and Cons of Each Approach**

1. **Spread Operator**:
	* Pros:
		+ Creates a new array, which can be beneficial for performance if you need to process the resulting array further.
		+ Can be more readable and concise than using `splice()`.
	* Cons:
		+ Requires creating a new array, which can be memory-intensive for large arrays.
2. **Splice Method**:
	* Pros:
		+ Modifies the original array in place, which can be beneficial for performance if you need to modify the original data.
		+ Can be more efficient than creating a new array using the spread operator.
	* Cons:
		+ Modifies the original array, which can be unexpected behavior if not used carefully.
		+ May have performance implications depending on the browser and JavaScript engine.

**Library**

There is no specific library mentioned in the benchmark definition. However, it's worth noting that both approaches use native JavaScript methods, so there are no external dependencies required for this benchmark.

**Special JS Feature or Syntax**

The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) and has become a widely supported feature across modern browsers and JavaScript engines. The `splice()` method, on the other hand, is an older method that has been part of the JavaScript language since its inception.

**Other Alternatives**

If you don't like using the spread operator or the `splice()` method, there are alternative approaches to remove elements from an array:

* Using `filter()`: `var output = array.filter((val, i) => i >= 38);`
* Using `map()`: `var output = array.map((val, i) => val === undefined ? null : val);`
* Using a custom loop: `for (var i = 0; i < 38; i++) { delete array[i]; }`

However, these alternatives may have different performance implications and might not be as concise or readable as the original approaches being compared in this benchmark.

Related benchmarks:

non-mutating array remove: spread and slice vs slice and splice (version: 0)

Comparing performance of: spread vs splice

Created: 7 years ago by: Guest

Jump to the latest result

spread

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):