Benchmark: flatten arrays 112412432

Script Preparation code:

var entries = 1000;
var a = [];
var b = [];
var c = [];
var d = [];
var e = [];
var f = [];
for (var i = 0; i < entries; i++) {
  a[i] = Math.random();
  b[i] = Math.random();
  c[i] = Math.random();
  d[i] = Math.random();
  e[i] = Math.random();
  f[i] = Math.random();
}
 var arrayOfArrays = [a, b, c, d, e, f];

Tests:

Array.flat()
var result1 = arrayOfArrays.flat();
Reduce
var result2 = arrayOfArrays.reduce((a, subArray) => a.concat(subArray), []);
forEach
var result3 = []; arrayOfArrays.forEach((subArray) => Array.prototype.push.apply(result3, subArray));
for
var result4 = []; for (var i = 0; i < arrayOfArrays.length; i++) { Array.prototype.push.apply(result4, arrayOfArrays[i]); }
Nested for
var result5 = []; for (var i = 0; i < arrayOfArrays.length; i++) { for (var j = 0; j < arrayOfArrays[i].length; j++) { result5.push(arrayOfArrays[i][j]); } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.flat()
Reduce
forEach
for
Nested for

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the benchmark and explain what's being tested, compared options, pros and cons of each approach, and other considerations.

**Benchmark Definition**

The benchmark definition is a JSON object that describes the test case:

```json
{
  "Name": "flatten arrays 112412432",
  "Description": null,
  "Script Preparation Code": "...",
  "Html Preparation Code": null
}
```

This code creates an array of six arrays (`arrayOfArrays`) with 1000 random numbers each. The script preparation code sets up the test case.

**Individual Test Cases**

The benchmark consists of four individual test cases:

1. `Array.flat()`
2. `Reduce`
3. `forEach`
4. `for`

Each test case has a unique JavaScript code snippet that flattens the `arrayOfArrays` using a different approach.

**Test Case Breakdown**

Here's a brief explanation of each test case:

### Array.flat()

```javascript
var result1 = arrayOfArrays.flat();
```

The `flat()` method returns a new array with all sub-array elements concatenated into it recursively up to the specified depth. In this case, since there are no sub-arrays within sub-arrays, it simply returns a new array containing all elements of `arrayOfArrays`.

### Reduce

```javascript
var result2 = arrayOfArrays.reduce((a, subArray) => a.concat(subArray), []);
```

The `reduce()` method applies a function against an accumulator and each element in the array (from left to right) to reduce it to a single value. In this case, it concatenates all sub-arrays into a single array using the `concat()` method.

### forEach

```javascript
var result3 = [];
arrayOfArrays.forEach((subArray) => Array.prototype.push.apply(result3, subArray));
```

The `forEach()` method executes a provided function once for each element in an array. In this case, it uses the `push()` method to add all elements of each sub-array to the `result3` array.

### for

```javascript
var result4 = [];
for (var i = 0; i < arrayOfArrays.length; i++) {
  Array.prototype.push.apply(result4, arrayOfArrays[i]);
}
```

This code uses a traditional `for` loop to iterate over each sub-array and adds its elements to the `result4` array using `push()`.

### Nested for

```javascript
var result5 = [];
for (var i = 0; i < arrayOfArrays.length; i++) {
  for (var j = 0; j < arrayOfArrays[i].length; j++) {
    result5.push(arrayOfArrays[i][j]);
  }
}
```

This code uses a nested `for` loop to iterate over each element in the sub-arrays and adds it to the `result5` array using `push()`.

**Comparison of Approaches**

Here's a brief comparison of each approach:

*   **Array.flat()**: This is the most efficient way to flatten an array, as it avoids creating intermediate arrays.
*   **Reduce**: While this method can be convenient for certain use cases, it creates an additional array and can be slower than `flat()` due to its extra overhead.
*   **forEach**: Using `forEach()` with `push()` is less efficient than using `flat()`, as it creates multiple intermediate arrays and has more function call overhead.
*   **for**: This approach requires more manual memory management and is generally slower than the others.

**Other Considerations**

When choosing an approach, consider the following factors:

*   **Performance**: If performance is a top priority, use `Array.flat()`.
*   **Convenience**: If readability and simplicity are more important, use `Reduce` or `forEach`.
*   **Memory Management**: If memory efficiency is crucial, use `Array.flat()` to avoid creating intermediate arrays.

**Alternatives**

Other alternatives for flattening arrays include:

*   Using `Array.prototype.reduce()` with a different callback function.
*   Using a library like Lodash's `flatten` function.
*   Using a recursive function to flatten the array.

In conclusion, when it comes to flattening an array, `Array.flat()` is usually the best choice for performance and memory efficiency. However, other approaches can be suitable depending on specific requirements or use cases.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36

Browser/OS: Chrome 74 on Mac OS X 10.14.5

View result in a separate tab

Test name	Executions per second
Array.flat()	993.8 Ops/sec
Reduce	47679.8 Ops/sec
forEach	21102.5 Ops/sec
for	20595.5 Ops/sec
Nested for	990.0 Ops/sec

Related benchmarks:

flatten arrays 112412432 (version: 0)

Comparing performance of: Array.flat() vs Reduce vs forEach vs for vs Nested for

Created: 5 years ago by: Guest

Jump to the latest result

Array.flat()

Reduce

forEach

for

Nested for

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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