Benchmark: Spread Operator VS Array.prototype.slice() VS Array.prototype.slice(0)

Script Preparation code:

var randomNumbers = [];

for (let i = 0; i < 2000; i++) {
    randomNumbers.push(Math.random());
}

Tests:

Spread Operation
const copy = [...randomNumbers];
Array.prototype.slice()
const copy = randomNumbers.slice();
Array.prototype.slice(0)
const copy = randomNumbers.slice(0);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread Operation
Array.prototype.slice()
Array.prototype.slice(0)

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Windows

View result in a separate tab

Test name	Executions per second
Spread Operation	1873710.0 Ops/sec
Array.prototype.slice()	1825417.0 Ops/sec
Array.prototype.slice(0)	1704650.2 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 benchmark measures the performance of three different approaches to create a copy of an array in JavaScript:

1. **Spread Operator (`const copy = [...randomNumbers];`)**: This approach creates a new array by spreading the elements of `randomNumbers`.
2. **Array.prototype.slice()` with no arguments (`const copy = randomNumbers.slice();`)**: This approach returns a shallow copy of `randomNumbers`, creating a new array.
3. **Array.prototype.slice()` with an argument (0) (`const copy = randomNumbers.slice(0);`)**: This approach creates a new array containing only the first element of each sub-array in `randomNumbers`.

**Options compared**

The benchmark compares the performance of these three approaches:

* Spread Operator
* Array.prototype.slice() without arguments
* Array.prototype.slice() with an argument (0)

**Pros and Cons of each approach:**

1. **Spread Operator (`const copy = [...randomNumbers];`)**:
	* Pros: Creates a new array, can be more efficient than other approaches for large arrays.
	* Cons: May not be as readable or maintainable as other options.
2. **Array.prototype.slice()` without arguments (`const copy = randomNumbers.slice();`)**:
	* Pros: Easy to read and understand, creates a shallow copy of the array.
	* Cons: May not create a new array for large arrays, can lead to unexpected behavior if used incorrectly.
3. **Array.prototype.slice()` with an argument (0) (`const copy = randomNumbers.slice(0);`)**:
	* Pros: Creates a new array containing only the first element of each sub-array in `randomNumbers`, can be more efficient than other approaches for large arrays.
	* Cons: May not create a new array, can lead to unexpected behavior if used incorrectly.

**Library and its purpose**

There is no external library used in this benchmark. However, JavaScript arrays are based on the ECMAScript specification, which defines the behavior of arrays and their methods, including `slice()`.

**Special JS feature or syntax**

There is no special JS feature or syntax mentioned in this benchmark.

**Other alternatives**

If you're looking for alternative approaches to create a copy of an array in JavaScript, some other options include:

* Using the `Array.prototype.concat()` method: `const copy = randomNumbers.concat();`
* Using the `JSON.parse(JSON.stringify(randomNumbers))` trick: `const copy = JSON.parse(JSON.stringify(randomNumbers));`
* Using a library like Lodash's `cloneDeep` function

Note that each of these alternatives has its own trade-offs and performance characteristics, which may be worth considering depending on your specific use case.

Related benchmarks:

Spread Operator VS Array.prototype.slice() VS Array.prototype.slice(0) (version: 0)

Spread Operator VS Array.prototype.slice() VS Array.prototype.slice(0)

Comparing performance of: Spread Operation vs Array.prototype.slice() vs Array.prototype.slice(0)

Created: 2 years ago by: Guest

Jump to the latest result

Spread Operation

Array.prototype.slice()

Array.prototype.slice(0)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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