Benchmark: flatten arrays 1124124323

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]); } }
Destructuring + reduce
var result6 = arrayOfArrays.reduce((a, subArray) => {a.push(...subArray); return a;}, []);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

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 break down the provided JSON data and explain what's being tested.

**Benchmark Definition**

The benchmark is designed to test the performance of different methods for flattening an array of arrays in JavaScript. The script preparation code generates an array of arrays (`arrayOfArrays`) with 1000 entries each, filled with random numbers.

**Test Cases**

There are six test cases:

1. **Array.flat()**: Tests the `flat()` method, which returns a new flattened array.
2. **Reduce**: Tests the `reduce()` method, which applies a callback function to each element of the array and returns a single value (in this case, an empty array).
3. **forEach**: Tests the `forEach()` method, which executes a provided function for each element in the array.
4. **for**: Tests a traditional `for` loop to iterate through each sub-array and push elements into a new array.
5. **Nested for**: Tests a nested `for` loop structure to flatten the arrays.
6. **Destructuring + reduce**: Tests a combination of destructuring assignment and `reduce()` methods.

**Options Compared**

Each test case compares different approaches to flattening the array:

* `Array.flat()`: uses the `flat()` method, which is a built-in JavaScript method.
* `Reduce`: uses the `reduce()` method with an accumulator variable and concatenation.
* `forEach`: uses the `forEach()` method with an iterator function.
* `for`: uses a traditional `for` loop with array iteration.
* `Nested for`: uses nested `for` loops to iterate through sub-arrays.
* `Destructuring + reduce`: uses destructuring assignment followed by `reduce()`.

**Pros and Cons**

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

1. **Array.flat()**: Fast, easy to use, and built-in. Pros: high performance, concise code. Cons: not all browsers support it.
2. **Reduce**: Flexible, but can be slower due to object creation. Pros: works with any iterable, flexible callback function. Cons: more verbose, potential performance issues.
3. **forEach**: Easy to use, but may incur additional overhead due to iterator functions. Pros: simple and concise, works with any iterable. Cons: potential performance issues, may require additional setup.
4. **for**: Traditional, straightforward approach. Pros: easy to understand, works with any array. Cons: verbose, can be slower than other methods.
5. **Nested for**: May incur higher overhead due to nested loops. Pros: ensures explicit iteration through sub-arrays. Cons: more complex and potentially slower.

**Library/Extensions Used**

None of the test cases rely on external libraries or extensions beyond standard JavaScript features.

**Special JS Features/Syntax**

No special JavaScript features or syntax are used in these test cases. The focus is on comparing the performance of built-in methods and traditional loop constructs.

**Alternatives**

For flattening arrays, other alternatives could include:

* `Array.prototype.concat()`: a more explicit approach using concatenation.
* `Array.prototype.map()`: can be used to flatten an array by mapping each element to an array with that element as its only element.
* Other libraries or modules, such as Lodash or Ramda, which provide additional utility functions for working with arrays.

However, the standard JavaScript methods (`flat()`, `reduce()`, and traditional loops) are still the most widely supported and efficient ways to flatten arrays.

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36

Browser/OS: Chrome 74 on Linux

View result in a separate tab

Test name	Executions per second
Array.flat()	796.1 Ops/sec
Reduce	38321.8 Ops/sec
forEach	16011.0 Ops/sec
for	15994.6 Ops/sec
Nested for	919.7 Ops/sec
Destructuring + reduce	3602.1 Ops/sec

Related benchmarks:

flatten arrays 1124124323 (version: 0)

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

Created: 5 years ago by: Guest

Jump to the latest result

Array.flat()

Reduce

forEach

for

Nested for

Destructuring + reduce

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):