Benchmark: Array.flat() vs. concat() + spreadOperator

Tests:

concat() + spread operator
var params = [[ 1, 2 ], [ "hello", true, 7 ]]; var other = [].concat(...params);
Array.flat()
var params = [[1, 2, params], [ "hello", true, 7 ]]; var other = params.flat();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat() + spread operator
Array.flat()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.1 Safari/605.1.15

Browser/OS: Safari 16 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
concat() + spread operator	9062733.0 Ops/sec
Array.flat()	7406549.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided benchmark.

**Benchmark Description**

The benchmark compares two approaches for flattening arrays:

1. `concat()` + spread operator (`...`): This method uses the spread operator to unpack an array and then concatenates its elements using the `concat()` method.
2. `Array.flat()`: This is a built-in JavaScript method introduced in ES6 (ECMAScript 2015) that flattens an array.

**Options Compared**

The benchmark tests two options for flattening arrays:

* **Approach 1: concat() + spread operator**
	+ Pros:
		- Widely supported and well-established
		- Can be used with older browsers that don't support `Array.flat()`
	+ Cons:
		- Less efficient than `Array.flat()` due to the overhead of concatenation
		- May lead to performance issues when dealing with large arrays
* **Approach 2: Array.flat()**
	+ Pros:
		- More efficient than the concat() + spread operator approach
		- Specifically designed for flattening arrays, making it more optimized
	+ Cons:
		- Less widely supported (introduced in ES6), which may limit its use in older browsers or environments

**Other Considerations**

When choosing between these approaches, consider the trade-offs between performance, compatibility, and code readability.

* **Code Readability**: `Array.flat()` is often considered more readable and concise than the concat() + spread operator approach.
* **Compatibility**: If you need to support older browsers that don't support ES6 features, the concat() + spread operator approach might be a better choice.

**Library Used**

There is no library used in this benchmark. Both approaches rely on built-in JavaScript methods: `concat()` and `Array.flat()`.

**Special JS Feature or Syntax**

No special JavaScript feature or syntax is used in this benchmark. The examples are simple and straightforward, using standard JavaScript syntax.

**Alternative Approaches**

If you need to flatten arrays, but don't want to use the concat() + spread operator approach:

* **Lodash**: A popular utility library for JavaScript that provides a `flatten()` method. This approach is more readable and efficient than the concat() + spread operator approach.
* **Array.prototype.flat()` (without spreading)**: You can call `flat()` directly on an array without using the spread operator (`...`). This approach is similar to `Array.flat()` but might not be as optimized.

Keep in mind that the performance benefits of using `Array.flat()` will depend on your specific use case and requirements. Always consider compatibility, readability, and performance when choosing a flattening method for your JavaScript arrays.

Related benchmarks:

Array.flat() vs. concat() + spreadOperator (version: 0)

Compare the Array.flat() to concat() + spread operator

Comparing performance of: concat() + spread operator vs Array.flat()

Created: 4 years ago by: Guest

Jump to the latest result

concat() + spread operator

Array.flat()

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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