Benchmark: Flat vs concat - MeasureThat.net

Tests:

Concat
let first = []; for (let i =0; i < 100; i++) { first.push(i); } let second = []; for (let i= 100; i < 200; i++) { second.push(i); } let third = []; for (let i =200; i < 300; i++) { third.push(i); } const concatResult = first.concat(second).concat(third);
Flat
let first = []; for (let i =0; i < 100; i++) { first.push(i); } let second = []; for (let i= 100; i < 200; i++) { second.push(i); } let third = []; for (let i =200; i < 300; i++) { third.push(i); } const flatResult = [first, second, third].flat();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Concat
Flat

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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**Benchmark Explanation**

The provided JSON represents two JavaScript microbenchmarks, "Flat" and "Concat", which compare the performance of two approaches to flatten arrays in JavaScript.

**Flattening Arrays in JavaScript**

In JavaScript, there are two ways to flatten an array:

1.  Using the `concat()` method: This method creates a new array by copying elements from another array or arrays.
2.  Using the spread operator (`...`): Introduced in ECMAScript 2015 (ES6), this operator spreads elements of an array into the parameter list.

**Benchmark Definition**

The benchmark definition for "Flat" uses the spread operator to flatten an array:
```javascript
const flatResult = [first, second, third].flat();
```
This code creates an array `[first, second, third]`, then calls `flat()` on it to create a new array with all elements flattened.

In contrast, the benchmark definition for "Concat" uses the `concat()` method:
```javascript
const concatResult = first.concat(second).concat(third);
```
This code creates an array `first` and pushes elements from another array `second`. It then concatenates this result with another array `third`.

**Options Compared**

The two benchmarks compare the performance of these two approaches:

1.  **Spread Operator (`...`)**: This approach is generally faster because it avoids creating intermediate arrays.
2.  **`concat()` Method**: This approach creates intermediate arrays, which can lead to increased memory usage and slower performance.

**Pros and Cons**

Here are some pros and cons of each approach:

### Spread Operator (`...`)

Pros:

*   Faster performance
*   Fewer intermediate arrays created

Cons:

*   Only available in ECMAScript 2015 (ES6) and later versions
*   May not work as expected with certain libraries or frameworks

### `concat()` Method

Pros:

*   Widely supported across browsers and platforms
*   Easy to understand and use for many developers

Cons:

*   Slower performance due to intermediate array creation
*   Higher memory usage compared to the spread operator

**Library Usage**

Neither of these benchmarks uses a specific library. The `flat()` method is a built-in JavaScript method, while the `concat()` method is also a built-in method.

**Special JS Features or Syntax**

This benchmark does not use any special JavaScript features or syntax beyond the use of the spread operator in the "Flat" test case.

**Other Alternatives**

If you're interested in exploring alternative approaches to flattening arrays, here are some options:

1.  **Using `reduce()`**: You can use the `reduce()` method to flatten an array:
    ```javascript
const flatResult = [first, second, third].reduce((acc, curr) => acc.concat(curr), []);
```
2.  **Using a library like Lodash**: If you're working with large datasets or need more advanced flattening capabilities, consider using a library like Lodash.
3.  **Using `Array.prototype.flat.call()`**: This method is similar to the spread operator but uses the `call()` method instead:
    ```javascript
const flatResult = Array.prototype.flat.call([first, second, third]);
```

These alternatives may offer better performance or more flexibility in certain scenarios, but they also introduce additional complexity and dependencies.

Related benchmarks:

Flat vs concat (version: 0)

Comparing performance of: Concat vs Flat

Created: 4 years ago by: Guest

Jump to the latest result

Concat

Flat

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):