Benchmark: Clone array - MeasureThat.net

Tests:

Array.from
const arr = new Array(100) for (let i = 0; i < arr.length; i++) { arr[i] = i } const clone = Array.from(arr)
Spread
const arr = new Array(100) for (let i = 0; i < arr.length; i++) { arr[i] = i } const clone = [...arr]
[].slice.call
const arr = new Array(100) for (let i = 0; i < arr.length; i++) { arr[i] = i } const clone = [].slice.call(arr)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.from
Spread
[].slice.call

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; rv:134.0) Gecko/20100101 Firefox/134.0

Browser/OS: Firefox 134 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Array.from	608474.3 Ops/sec
Spread	653184.8 Ops/sec
[].slice.call	2113218.5 Ops/sec

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

LLMs can make mistakes. Check important info.

**What is tested on the provided JSON?**

The provided JSON represents a JavaScript microbenchmark test case that compares three different approaches for cloning an array:

1. `Array.from()`
2. Spread operator (`...`)
3. `[].slice.call()` (also known as the "array slice" method)

These approaches are compared in terms of their execution time and performance.

**Options being compared:**

* `Array.from()`: Creates a new array from an existing array or iterable.
* Spread operator (`...`): Spreads the elements of one array to another array.
* `[].slice.call()` (also known as "array slice"): Returns a new array containing all elements from the original array.

**Pros and Cons:**

1. **Array.from()**
	* Pros:
		+ Can create an array from any iterable (e.g., strings, objects).
		+ More concise syntax.
	* Cons:
		+ May have overhead due to the creation of a new array.
2. Spread operator (`...`):
	* Pros:
		+ Fast and efficient for cloning arrays.
		+ Can be used with other data types (e.g., strings, objects).
	* Cons:
		+ May not work as expected if the spreadable value is an object or a function.
3. `[].slice.call()` (array slice):
	* Pros:
		+ Fast and efficient for cloning arrays.
	* Cons:
		+ Less concise syntax compared to `Array.from()` and spread operator.

**Library used:**

None.

**Special JS feature or syntax:**

None mentioned in the provided code.

**Benchmark preparation code:**

The benchmark preparation code creates a new array with 100 elements, populates it with numbers from 0 to 99, and then clones it using each of the three approaches being compared. The resulting cloned arrays are used as input for the benchmarking test.

**Other alternatives:**

There might be other ways to clone an array in JavaScript, such as using `Array.prototype.concat()` or `Buffer.from()`, but these are not part of the provided benchmark definition.

Some alternative approaches could be:

* Using a library like Lodash (e.g., `_cloneArray`) for cloning arrays.
* Using a functional programming approach with `map` and `reduce` methods to clone an array.
* Using a native method like `Int8Array.from()` or `Uint8Array.from()` for cloning arrays.

However, these alternatives are not part of the standard JavaScript API and may have different performance characteristics compared to the approaches being compared in this benchmark.

Related benchmarks:

Clone array (version: 3)

Array.from vs spread vs [].slice.call

Comparing performance of: Array.from vs Spread vs [].slice.call

Created: 7 years ago by: Registered User

Jump to the latest result

Array.from

Spread

[].slice.call

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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