Benchmark: copy-array - MeasureThat.net

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

var arr = Array.from(Array(500000).keys());

Tests:

slice
const arr1 = arr.slice();
concat
const arr2 = [].concat(arr);
spread operator
const arr3 = [...arr];
_.clone
const arr4 = _.clone(arr);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
concat
spread operator
_.clone

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of MeasureThat.net, a website that allows users to create and run JavaScript microbenchmarks.

**Benchmark Definition JSON**

The provided benchmark definition JSON represents a collection of test cases for measuring the performance of different methods for copying arrays in JavaScript. The JSON contains:

* `Name`: a unique identifier for the benchmark
* `Description`: an optional description of the benchmark (in this case, empty)
* `Script Preparation Code`: a snippet of JavaScript code that prepares the array to be copied (`var arr = Array.from(Array(500000).keys());`)
* `Html Preparation Code`: a snippet of HTML code that includes a reference to the Lodash library (`\r\n<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>`)

**Test Cases**

The test cases are defined in an array, each containing:

* `Benchmark Definition`: a string representing the JavaScript code that measures the performance of a specific method for copying arrays (e.g., `const arr1 = arr.slice();`)
* `Test Name`: a human-readable name for the test case

There are four test cases: `slice`, `concat`, `spread operator`, and `_.clone`. Each test case corresponds to a different method for copying arrays in JavaScript.

**Library**

The Lodash library is used in the benchmark definition JSON. Lodash is a popular utility library that provides a collection of functional programming helpers, including functions for working with arrays. In this benchmark, the `_` symbol is used as an alias for the Lodash namespace. The `_.clone()` function is specifically used to clone the array.

**Options Compared**

The test cases compare four different methods for copying arrays:

1. **Slice**: uses the `slice()` method to create a shallow copy of the array
2. **Concat**: uses the `concat()` method to concatenate two or more arrays
3. **Spread Operator**: uses the spread operator (`...`) to create a new array by spreading the elements of the original array
4. **_.Clone** (Lodash): uses the `_clone()` function from Lodash to create a deep copy of the array

**Pros and Cons**

Here's a brief summary of the pros and cons of each method:

* **Slice**: fast, but can be slow for large arrays due to the need to create a new array object
* **Concat**: can be slow for large arrays due to the need to create multiple intermediate arrays
* **Spread Operator**: relatively fast, but can be slower than slice for very large arrays
* **_.Clone** (Lodash): provides a deep copy of the array, which can be beneficial in certain scenarios, but may incur additional overhead

**Other Considerations**

When choosing an method for copying arrays, consider factors such as:

* Performance: how quickly does the method need to execute?
* Memory usage: how much memory will the new array occupy?
* Data integrity: does the method preserve the original array's structure and data?

**Alternatives**

If you're looking for alternative methods for copying arrays in JavaScript, consider:

* Using a library like Lodash or Underscore.js that provides an implementation of `clone()` or similar functions
* Implementing your own array cloning function using a combination of `slice()`, `concat()`, and/or the spread operator
* Using a third-party library that provides optimized array cloning functionality

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36

Browser/OS: Chrome 71 on Mac OS X 10.14.2

View result in a separate tab

Test name	Executions per second
slice	241.0 Ops/sec
concat	230.2 Ops/sec
spread operator	249.4 Ops/sec
_.clone	205.4 Ops/sec

Related benchmarks:

copy-array (version: 0)

Comparing performance of: slice vs concat vs spread operator vs _.clone

Created: 5 years ago by: Guest

Jump to the latest result

slice

concat

spread operator

_.clone

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):