Benchmark: clone array performance test

HTML Preparation code:

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.4/lodash.min.js"></script>

Script Preparation code:

var og = []
for (let index = 0; index < 5; index++) {
    og.push({index: index})
    
}

Tests:

map Object.assign
const newArray = og.map(a => Object.assign({}, a));
map spread
const newArray = og.map(a => ({...a}));
JSON
const newArray = JSON.parse(JSON.stringify(og))
_.cloneDeep
const newArray = _.cloneDeep(og)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map Object.assign
map spread
JSON
_.cloneDeep

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

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**Benchmark Overview**

The provided benchmark measures the performance of different methods for cloning an array in JavaScript. The test is designed to compare various approaches, including using `map()` with `Object.assign()`, `map` with object spread (`...a)` syntax, `JSON.parse(JSON.stringify())`, and `_.cloneDeep()` from the Lodash library.

**Options Compared**

The benchmark compares four different methods for cloning an array:

1. **`map Object.assign`**: This approach uses the `map()` function to create a new array with the original elements, and then assigns each element using `Object.assign()`.
2. **`map spread`**: Similar to the previous method, but uses the object spread syntax (`...a`) instead of `Object.assign()`.
3. **`JSON`**: This approach uses `JSON.parse(JSON.stringify(og))`, which serializes the original array and then parses it back into a new array.
4. **`_.cloneDeep()`**: This approach uses the `cloneDeep()` function from Lodash, which creates a deep clone of the original array.

**Pros and Cons**

Here are some pros and cons for each approach:

1. **`map Object.assign`**:
	* Pros: Simple to implement, easy to understand.
	* Cons: Can be slower than other methods due to the overhead of `Object.assign()`.
2. **`map spread`**:
	* Pros: Similar performance to `map Object.assign`, with the added benefit of being more concise and readable.
	* Cons: Still has the overhead of creating a new array, which can impact performance for large datasets.
3. **`JSON`**:
	* Pros: Simple and concise implementation.
	* Cons: Can be slower than other methods due to the overhead of serializing and parsing JSON data.
4. **`_.cloneDeep()`**:
	* Pros: Creates a deep clone, which can be important for preserving array structures.
	* Cons: Uses an external library (Lodash), which may not be desirable for all projects.

**Library Usage**

In this benchmark, the Lodash library is used to provide the `_.cloneDeep()` function. The library is loaded via a script tag in the HTML preparation code (`<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.4/lodash.min.js"></script>`).

**Special JS Features or Syntax**

None of the benchmark tests use any special JavaScript features or syntax beyond what is typically supported by modern browsers.

**Other Alternatives**

If you're interested in exploring alternative methods for cloning arrays, here are a few options:

* **`Array.prototype.slice()`**: Creates a shallow copy of the original array.
* **`Array.prototype.concat()`**: Creates a new array by concatenating the original array with an empty array.
* **`Array.prototype.reduce()`**: Creates a new array by reducing the original array to a single element.

Note that these alternatives may have different performance characteristics and use cases compared to the methods tested in this benchmark.

Related benchmarks:

clone array performance test (version: 0)

Comparing performance of: map Object.assign vs map spread vs JSON vs _.cloneDeep

Created: 4 years ago by: Guest

Jump to the latest result

map Object.assign

map spread

JSON

_.cloneDeep

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):