Benchmark: concat(spreadOp) vs flat()

Tests:

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

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser/OS: Chrome 87 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
reduce + Array.prototype.concat	6044188.0 Ops/sec
Array.prototype.flat	857685.6 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in the provided JSON.

**Benchmark Definition**

The benchmark is designed to compare two approaches for concatenating arrays:

1. `Array.prototype.concat() + spread operator` (denoted by the spread operator `...`)
2. `Array.prototype.flat()` (introduced in ECMAScript 2019)

**Options Compared**

The benchmark tests the performance of these two approaches on a specific use case: reducing an array of arrays using `Array.prototype.reduce()`, which requires concatenating intermediate results.

**Pros and Cons**

1. **Array.prototype.concat() + spread operator**: This approach is widely supported by older browsers that don't have native support for `flat()`. However, it may be slower than `flat()` since it involves additional overhead from concatenating arrays.
2. **Array.prototype.flat()**: This approach is a more modern and efficient way to flatten arrays. It's also more concise and easier to read, making it a better choice for new codebases. However, its performance may vary depending on the browser support.

**Library Usage**

There are no specific libraries used in this benchmark.

**Special JS Features or Syntax**

The benchmark uses ES6+ features like:

* Spread operator (`...`)
* ECMAScript 2019 (ES9) feature: `Array.prototype.flat()`

These features are widely supported by modern browsers, including Chrome 87.

**Other Considerations**

The benchmark is designed to provide a fair comparison between the two approaches. However, other factors that might affect performance, such as array size and shape, are not taken into account.

Some alternatives to consider:

* Using `Array.prototype.reduce()` with a custom flattening function instead of concatenating arrays.
* Using a third-party library like Lodash or Underscore.js for more advanced array manipulation.
* Optimizing the benchmark for specific use cases or performance-critical parts of the codebase.

Related benchmarks:

concat(spreadOp) vs flat() (version: 0)

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

Comparing performance of: reduce + Array.prototype.concat vs Array.prototype.flat

Created: 4 years ago by: Guest

Jump to the latest result

reduce + Array.prototype.concat

Array.prototype.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):