Benchmark: Array.prototype.slice vs spread operator - objects 22

Script Preparation code:

    function fromNumberToObject(id = 0) {
      return {
        id,
        value: id + id,
        name: 'example',
      };
    }
    var list = [...Array(99999999).keys()].map(fromNumberToObject);

Tests:

Array.prototype.slice
const test = list.slice();
spread operator
const test = [...list];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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):

LLMs can make mistakes. Check important info.

Let's dive into the provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark compares two approaches to create a shallow copy of an array:

1. **`Array.prototype.slice()`**: This method creates a new array that contains a subset of elements from the original array, starting from a specified index (in this case, 0) up to, but not including, the end of the array.
2. **The Spread Operator (`...`)**: This operator creates a new array by taking all elements from an existing array and placing them into a new array.

**Options being compared**

The benchmark is comparing the performance of these two approaches:

* `Array.prototype.slice()`
* The Spread Operator (`...`)

**Pros and Cons of each approach:**

1. **`Array.prototype.slice()`**
	* Pros:
		+ Efficient for large arrays, as it only creates a new array with references to the original elements.
		+ Well-supported by most browsers and Node.js versions.
	* Cons:
		+ Can be slower for small arrays or when creating a shallow copy of an object (since `slice()` returns an object reference).
2. **The Spread Operator (`...`)**
	* Pros:
		+ Creates a new array with cloned values, which can improve performance and security when working with large datasets.
		+ Simplifies code by avoiding the need to create an array using `Array.prototype.slice()`.
	* Cons:
		+ Can be slower for very large arrays or when working with older browsers/Node.js versions that don't support the Spread Operator.
		+ Requires modern JavaScript features and a compatible browser/Node.js environment.

**Library usage**

There is no library being used in this benchmark. The `fromNumberToObject()` function is defined inline, but it's not using any external libraries.

**Special JS feature or syntax**

The Benchmark Definition uses the ES6 spread operator (`...`), which is a new syntax introduced in ECMAScript 2015 (ES6). This syntax allows for creating a new array by taking all elements from an existing array and placing them into a new array. The `Array.prototype.slice()` method, on the other hand, is a legacy function that has been around since JavaScript's inception.

**Other alternatives**

If you needed to create a shallow copy of an array in older browsers or Node.js versions, you could use alternative approaches, such as:

* `Array.prototype.concat()`: Creates a new array by concatenating the original array with an empty array.
* `Object.assign()`: Copies values from one object to another.
* Using a library like Lodash (specifically, the `cloneDeep()` function) to create a deep copy of an array.

However, these alternatives may have different performance characteristics and compatibility issues compared to `Array.prototype.slice()` or the Spread Operator.

Related benchmarks:

Array.prototype.slice vs spread operator - objects 22 (version: 0)

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

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

Created: 5 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):