Benchmark: Spreading + Concat vs flat

Script Preparation code:

let array2D = [];
const n = 1000;
const c = 100;
for (let i = 0; i < n; i++) {
  let array1D = [];
  for (let k = 0; k < c; k++) {
    array1D.push(k); 
  }
  array2D.push(array1D);
}
window.array2D = array2D;

Tests:

Spreading + concat
let result1 = [].concat(...window.array2D);
Flat
let result = window.array2D.flat();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spreading + 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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Let's dive into the provided benchmarking data.

**Benchmark Definition and Script Preparation Code**

The benchmark is comparing two approaches to flatten a 2D array in JavaScript: using `Array.prototype.concat()` with spreading (`...`) and using the `flat()` method.

The script preparation code creates a large 2D array `array2D` with dimensions `n x c`, where `n = 1000` and `c = 100`. This array is then assigned to the global scope (`window.array2D`).

**Options Compared**

Two options are compared:

1. **Spreading + Concat**: The first option uses the spreading operator (`...`) to flatten the 2D array, followed by the `concat()` method.
2. **Flat**: The second option directly calls the `flat()` method on the 2D array.

**Pros and Cons of Each Approach**

* **Spreading + Concat**:
	+ Pros: Easy to understand, widely supported across browsers.
	+ Cons: May be slower than using `flat()`, as it involves multiple steps (spreading, concatenation).
* **Flat**:
	+ Pros: Fastest and most efficient, as it's a native method in modern JavaScript arrays.
	+ Cons: Requires support for the `flat()` method in older browsers, which may not be the case.

**Library and Purpose**

In neither of the benchmarked test cases does the code use any additional libraries. However, if we were to extend the scope of the comparison, we'd likely encounter libraries like Lodash or Ramda, which provide utility functions for array manipulation, including flattening arrays.

**Special JS Feature or Syntax**

There are no special JavaScript features or syntaxes used in this benchmarking code. The focus is on comparing two basic approaches to flatten a 2D array.

**Other Alternatives**

Other alternatives to compare the performance of array flattening include:

* Using `Array.prototype.reduce()` to flatten the array.
* Utilizing a library like Lodash or Ramda, which provide optimized and tested implementations for array manipulation tasks.
* Implementing a custom loop-based solution to flatten the array.

When preparing this benchmark, you would need to ensure that the script preparation code is executed in isolation, without any external dependencies or optimizations. The individual test cases should be run multiple times to capture representative results, taking care not to skew the output with variations in input data or system load.

Related benchmarks:

Spreading + Concat vs flat (version: 0)

Comparing performance of: Spreading + concat vs Flat

Created: 5 years ago by: Guest

Jump to the latest result

Spreading + 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):