Benchmark: Array<string>.join vs Array<string>.reduce

Script Preparation code:

var strings = [...Array(1000).keys()].map(i => '' + i)

Tests:

join
var joined = strings.join(',')
reduce
var reduced = strings.reduce((acc, cur) => acc + ',' + cur)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
join
reduce

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 28 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36 Edg/146.0.0.0

Browser/OS: Chrome 146 on Windows

View result in a separate tab

Test name	Executions per second
join	45679.5 Ops/sec
reduce	100193.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares the performance of two ways to concatenate an array of strings in JavaScript: `join()` and `reduce()`. The test creates an array of 1000 string elements, ranging from 0 to 999, and then uses each method to concatenate all the strings into a single string.

**Options Compared**

Two options are compared:

1. **`join()`**: This method takes an array of strings as input and returns a new string with all the strings concatenated together using a separator (in this case, a comma).
2. **`reduce()`**: This method takes a callback function as input, which is applied to each element in the array. The callback function takes two arguments: the accumulator (initially set to an empty string) and the current element.

**Pros and Cons**

Here are some pros and cons of each approach:

* `join()`:
	+ Pros:
		- Simple and intuitive
		- Fast, as it uses a specialized implementation in V8 (the JavaScript engine used by Google Chrome)
	+ Cons:
		- Requires a separator string to be passed explicitly
		- May not be suitable for all use cases (e.g., concatenating arrays of different types)
* `reduce()`:
	+ Pros:
		- Flexible, as the callback function can be customized to handle any concatenation logic
		- Can be used with other data structures and algorithms
	+ Cons:
		- Less intuitive than `join()`
		- May incur a performance overhead due to the additional memory allocation required for the accumulator

**Library**

None.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax being tested in this benchmark.

**Other Alternatives**

Two other alternatives could be used instead of `join()` and `reduce()`, depending on the specific use case:

1. **`Array.prototype.concat()`**: This method concatenates two arrays into a new array, which can then be converted to a string using `toString()` or another concatenation method.
2. **`String.prototype.repeat()`**: This method repeats a string a specified number of times and returns a new string containing all the repeated strings.

In summary, this benchmark compares the performance of two common ways to concatenate arrays of strings in JavaScript: `join()` and `reduce()`. While `join()` is simple and fast, it may require additional separators, whereas `reduce()` provides more flexibility but can be less intuitive.

Related benchmarks:

Array<string>.join vs Array<string>.reduce (version: 0)

Comparing performance of: join vs reduce

Created: 4 years ago by: Guest

Jump to the latest result

join

reduce

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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