Benchmark: Lodash flatten v.s. Spread

HTML Preparation code:

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

Script Preparation code:

let ary = [1, [2, [3]]]

Tests:

lodash flatten
let ary = [1, [2, [3]]] return _.flatten(ary)
spread
let ary = [1, [2, [3]]] return [].concat(...ary)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash flatten
spread

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 and explain what's being tested.

**Benchmark Overview**

The benchmark compares two approaches to flatten an array with nested arrays: `lodash.flatten` and the spread operator (`...`). The goal is to determine which approach is faster.

**Script Preparation Code**

The script preparation code creates a simple array with one element, which is another array with three elements:
```javascript
let ary = [1, [2, [3]]];
```
This creates a nested array structure: `[1, [2, [3]]]`.

**Html Preparation Code**

The HTML preparation code includes the `lodash.js` library, which is used by the first test case (`lodash flatten`). This library provides a utility function for flattening arrays.

**Test Cases**

There are two individual test cases:

### Test Case 1: Lodash Flatten

```javascript
Benchmark Definition:
let ary = [1, [2, [3]]];
return _.flatten(ary);
```
This test case uses the `lodash.flatten` function to flatten the array. The `_` symbol refers to the global `lodash` namespace, which is imported from the included library.

**Pros:**

* Easy to use and understand for developers familiar with Lodash.
* Provides a consistent way of flattening arrays across different browsers.

**Cons:**

* Adds an external dependency (Lodash), which may not be present in all environments.
* May have slower execution due to the overhead of importing a library.

### Test Case 2: Spread Operator

```javascript
Benchmark Definition:
let ary = [1, [2, [3]]];
return [].concat(...ary);
```
This test case uses the spread operator (`...`) to flatten the array. The `concat` method is used with an empty array as the first argument and the input array as the second argument.

**Pros:**

* Does not add any external dependencies.
* Can be more efficient in some cases, as it avoids the overhead of importing a library.

**Cons:**

* May require additional processing to handle edge cases (e.g., when the input array contains non-arrays).
* Requires knowledge of the spread operator syntax for developers unfamiliar with it.

**Other Alternatives**

In addition to these two approaches, there are other ways to flatten arrays in JavaScript:

* `Array.prototype.flat()` method (introduced in ECMAScript 2019): This method returns a new array with one level of nested arrays flattened.
* Recursive function calls: You can write a recursive function that flattens the array by iterating through its elements and calling itself for each nested array.

However, these alternatives are not tested in this benchmark.

**Special JavaScript Feature**

The spread operator (`...`) is a relatively recent feature introduced in ECMAScript 2015 (ES6). It allows you to expand an array into a new array with the same elements. This feature is widely supported across modern browsers and Node.js environments.

In summary, the `lodash.flatten` approach provides a consistent way of flattening arrays but adds an external dependency, while the spread operator approach avoids this overhead but requires additional processing for edge cases.

Related benchmarks:

Lodash flatten v.s. Spread (version: 0)

Comparing performance of: lodash flatten vs spread

Created: 5 years ago by: Guest

Jump to the latest result

lodash flatten

spread

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):