Benchmark: Spread vs Slice - MeasureThat.net

HTML Preparation code:


<div id='x'></div>

Script Preparation code:

var el = document.getElementById('x');
function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

Tests:

Array.slice
var list = Array.prototype.slice.apply(el.classList);
Babel spread
var list = [].concat(_toConsumableArray(el.classList));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.slice
Babel spread

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.

I'll break down the explanation into smaller sections for better understanding.

**Benchmark Purpose and Description**

The provided benchmark measures the performance of two approaches to convert a `classList` object (a collection of class names) into an array:

1. **Array.prototype.slice.apply()**: This method uses the traditional JavaScript way to create an array from another iterable, such as an array or a string.
2. **Babel spread syntax ( [...classList] )**: This is a shorthand syntax introduced in modern JavaScript versions. It allows for spreading the `classList` object into an array.

**Options Comparison**

The benchmark compares these two approaches:

* **Array.prototype.slice.apply()**: This method has been around since ancient times and is widely supported across browsers. However, it's not as efficient or concise as the spread syntax.
* **Babel spread syntax ( [...classList] )**: This syntax is a more modern way to achieve the same result. It's concise, readable, and often faster due to its native support.

**Pros and Cons**

Here are the pros and cons of each approach:

1. **Array.prototype.slice.apply()**:
	* Pros: Wide browser support, easy to implement.
	* Cons: Can be slow and verbose, not as efficient as modern syntax.
2. **Babel spread syntax ( [...classList] )**:
	* Pros: Fast, concise, and readable.
	* Cons: Requires modern JavaScript version support and may break older browsers.

**Library Usage**

None of the test cases use any external libraries.

**Special JS Features or Syntax**

There's no mention of special JavaScript features or syntax. The benchmark focuses on comparing two simple approaches to array creation.

**Other Alternatives**

Some alternative approaches to create an array from a `classList` object include:

* Using `Array.from()` method (introduced in ECMAScript 2015): `var list = Array.from(el.classList);`
* Using the spread operator with `Object.values()` method: `var list = [...el.classList];`

Keep in mind that these alternatives might not be as efficient or concise as the spread syntax.

**Benchmark Preparation Code**

The provided preparation code sets up a test environment:

1. It retrieves an HTML element (`<div id='x'>`) using `document.getElementById()`.
2. It defines a utility function `_toConsumableArray()` to convert an iterable into an array.

**Individual Test Cases**

Each test case defines a single benchmark:

1. **"Array.slice"`**: Creates an array from the `classList` object using `Array.prototype.slice.apply()`.
2. **"Babel spread"`**: Creates an array from the `classList` object using the Babel spread syntax ( [...classList] ).

Related benchmarks:

Spread vs Slice (version: 0)

Cast a classList to an array with Array.prototype.slice.apply() or the babel transpile of [...classList]

Comparing performance of: Array.slice vs Babel spread

Created: 8 years ago by: Registered User

Jump to the latest result

Array.slice

Babel spread

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):