Benchmark: Array.prototype.slice vs spread operator vs copy

Tests:

Array.prototype.slice
var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].slice();
spread operator
var params = [ "hello", true, 7 ] var other = [ ...params ]
copy
var params = [ "hello", true, 7 ] var other = []; for (i = 0; i < 3; i++) { other[i] = params[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.slice
spread operator
copy

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 dive into the world of JavaScript microbenchmarks.

**What is being tested?**

The provided JSON represents a benchmark comparison between three approaches to create a copy of an array in JavaScript:

1. `Array.prototype.slice()`
2. The new ES6 spread operator (`[ ...params ]`)
3. Manual copying using a `for` loop

These three approaches are compared to determine which one is the most efficient.

**Options compared:**

* `Array.prototype.slice()`: A traditional method to create a copy of an array, which creates a new array and copies the elements from the original array.
* Spread operator (`[ ...params ]`): A newer method introduced in ES6 that uses destructuring syntax to create a new array with the elements of the original array.
* Manual copying using a `for` loop: This approach involves looping through the original array and assigning each element to a new location, typically using an array or object.

**Pros and cons of each approach:**

1. **Array.prototype.slice()**:
	* Pros:
		+ Widely supported across browsers
		+ Easy to understand and implement
	* Cons:
		+ Creates a new array, which can lead to higher memory usage
2. Spread operator (`[ ...params ]`):
	* Pros:
		+ More concise and readable than traditional `slice()`
		+ Efficiently creates a shallow copy of the original array
	* Cons:
		+ Requires modern browsers that support ES6 syntax
3. Manual copying using a `for` loop:
	* Pros:
		+ No additional dependencies or syntax requirements
		+ Can be used in older browsers
	* Cons:
		+ Longer and more verbose than traditional `slice()`
		+ Can lead to higher overhead due to explicit looping

**Libraries and their purpose:**

None of the provided benchmark definitions use a specific library, but they do rely on built-in JavaScript features.

**Special JS feature or syntax:**

The spread operator (`[ ...params ]`) is a newer JavaScript feature introduced in ES6. It allows for concise array creation using destructuring syntax.

**Other alternatives:**

In addition to the three approaches mentioned, there are other ways to create an array copy in JavaScript:

* `Array.prototype.concat()`: Creates a new array and concatenates the elements of the original array.
* `Object.assign()`: Copies properties from an object into a new object.
* `JSON.parse(JSON.stringify(obj))`: Creates a deep copy of an object by parsing its JSON representation.

However, these alternatives are not directly comparable to the three approaches mentioned in this benchmark.

Related benchmarks:

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

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

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

Created: 5 years ago by: Guest

Jump to the latest result

Array.prototype.slice

spread operator

copy

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):