Benchmark: Array.prototype.slice vs spread operator - objects - 30k

Script Preparation code:

    function fromNumberToObject(id = 0) {
      return {
        id,
        value: id + id,
        name: 'example',
      };
    }
    var list = [...Array(30000).keys()].map(fromNumberToObject);

Tests:

Array.prototype.slice
list.slice();
spread operator
[...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

Latest run results:

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

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Let's break down the provided benchmark definition and test cases.

**Benchmark Definition:**

The benchmark compares two approaches to creating an array of objects:

1. `Array.prototype.slice()` method
2. ES6 spread operator (`...`)

**Script Preparation Code:**
```javascript
function fromNumberToObject(id = 0) {
  return {
    id,
    value: id + id,
    name: 'example',
  };
}

var list = [...Array(30000).keys()].map(fromNumberToObject);
```
This code creates an array of 30,000 objects using the `fromNumberToObject` function and the spread operator (`...`). The `fromNumberToObject` function returns an object with three properties: `id`, `value`, and `name`. The `key` values are generated from `[Array(30000).keys()]`, which creates an array of numbers from 0 to 29,999.

**Html Preparation Code:** (not provided)

Since the HTML preparation code is not provided, we assume that it's empty or doesn't affect the benchmarking results.

**Individual Test Cases:**

There are two test cases:

1. `list.slice();`
2. `[...list];`

These test cases compare the performance of creating an array using the `slice()` method versus the spread operator (`...`).

**Pros and Cons of Different Approaches:**

* **Array.prototype.slice():**
	+ Pros:
		- Well-established and widely supported method.
		- Can be optimized by browsers for certain use cases (e.g., reducing the number of elements).
	+ Cons:
		- May not be as efficient as modern spread operators, especially for large arrays.
* **ES6 Spread Operator (`...`):**
	+ Pros:
		- More concise and expressive than `slice()`.
		- Can be optimized by browsers for certain use cases (e.g., using SIMD instructions).
	+ Cons:
		- May not be as widely supported or understood as `slice()`.

**Library Usage:**

None explicitly mentioned in the provided code. However, the spread operator uses the `Array.prototype.slice()` method internally to create an array-like object from which it extracts elements.

**Special JavaScript Features/Syntax:**

* The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) and provides a more concise way to create arrays or objects by "spreading" existing values.
* `slice()` method is a built-in Array prototype method that creates a shallow copy of an array.

**Other Alternatives:**

For creating an array of objects, you could also consider using:

1. `Array.from()` with an iterator or array-like object.
2. `Array.of()` (ES6) with the spread operator.
3. Other libraries like Lodash or Ramda for more complex transformations and utilities.

However, in this specific benchmark, only two approaches are being compared: the traditional `slice()` method and the ES6 spread operator (`...`).

Related benchmarks:

Array.prototype.slice vs spread operator - objects - 30k (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):