Benchmark: Array.prototype.slice vs spread operator (fixed)

Tests:

Array.prototype.slice
var params = [ "hello", true, 7 ]; var other = params.slice();
spread operator
var params = [ "hello", true, 7 ] var other = [ ...params ]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

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Test case name	Result
Array.prototype.slice
spread operator

Fastest: N/A

Slowest: N/A

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

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Let's break down what's being tested in the provided JSON benchmark.

**Benchmark Definition**

The benchmark is designed to compare two approaches for creating a copy of an array: the traditional `Array.prototype.slice()` method and the new ES6 spread operator (`[ ...params ]`).

**Options Compared**

Two options are compared:

1. **Array.prototype.slice()**: This method creates a shallow copy of an array by returning a new array object with references to the same elements as the original array.
2. **Spread Operator ([ ...params ])**: This method creates a new array by spreading the elements of the `params` array into a new array.

**Pros and Cons**

* **Array.prototype.slice()**:
	+ Pros: Generally faster, more widely supported, and easier to understand for older browsers that don't support the spread operator.
	+ Cons: Creates a shallow copy, which can lead to unexpected behavior if the original array contains mutable objects. Also, it returns an array with the same length as the original array, even if some elements are null or undefined.
* **Spread Operator ([ ...params ])**:
	+ Pros: Creates a deep copy of the array (if necessary), and is more concise and readable than `Array.prototype.slice()`.
	+ Cons: Requires JavaScript engines that support the spread operator (introduced in ECMAScript 2015). It's also slower than `Array.prototype.slice()`.

**Library Used**

None. This benchmark doesn't rely on any external libraries.

**Special JS Feature/Syntax**

The test case uses the spread operator, which is a relatively recent feature introduced in ECMAScript 2015 (ES6).

**Other Considerations**

When deciding between these two approaches, consider the trade-offs:

* If you need to create a shallow copy of an array with no deep copying required, `Array.prototype.slice()` might be sufficient. However, if you need to ensure that all elements are copied deeply, the spread operator is likely a better choice.
* Keep in mind that both methods have performance implications: `Array.prototype.slice()` tends to be faster but may not preserve the original array's structure, while the spread operator creates a deeper copy.

**Alternative Approaches**

Other alternatives for creating an array copy include:

1. **`Array.prototype.concat()`**: Creates a new array with copies of all elements from both arrays.
2. **`Array.prototype.slice.call()`**: Creates a new array with copies of all elements from the original array, using the `call()` method to specify the array constructor.
3. **`JSON.parse(JSON.stringify())`**: Creates a deep copy of an object (not an array) by parsing a JSON string representation of the original object.

These alternatives have different trade-offs and might not be suitable for all use cases. The spread operator is often considered a modern, concise, and efficient way to create array copies, but its support varies across browsers and JavaScript engines.

Related benchmarks:

Array.prototype.slice vs spread operator (fixed) (version: 0)

Compare the new ES6 spread operator with the traditional slice() method

Comparing performance of: Array.prototype.slice vs spread operator

Created: 3 years ago by: Guest

Jump to the latest result

Array.prototype.slice

spread operator

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):