Benchmark: Reduce and join in javascript

Script Preparation code:

var str = "";
var i;
var sArr = [];
for (i = 1000; i > 0; i--) {
	sArr[i] = "String concatenation. ";
}

Tests:

Join
str = sArr.join("");
Reduce
str = sArr.reduce((a, v) => a += `${v} `, '');

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: 2 years ago)

User agent: Mozilla/5.0 (Android 13; Mobile; rv:122.0) Gecko/122.0 Firefox/122.0

Browser/OS: Firefox Mobile 122 on Android

View result in a separate tab

Test name	Executions per second
Join	10507.1 Ops/sec
Reduce	8302.9 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 provided benchmark and explain what's being tested.

**Benchmark Overview**

The test measures the performance of two JavaScript methods: `join()` and `reduce()`. Both methods are used to concatenate an array of strings into a single string.

**Test Cases**

There are two test cases:

1. **Join**: This test case measures the performance of the `join()` method, which concatenates all elements in the `sArr` array with a specified separator (in this case, an empty string).
2. **Reduce**: This test case measures the performance of the `reduce()` method, which applies a callback function to each element in the `sArr` array and returns a single value.

**Options Compared**

The benchmark compares two approaches for concatenating strings:

1. **join()**: This is the most common way to concatenate an array of strings in JavaScript.
2. **reduce()**: This method uses a callback function to accumulate the values from each element in the array into a single string.

**Pros and Cons of Each Approach**

* **join()**:
	+ Pros: Simple, efficient, and widely supported.
	+ Cons: Can be slower for very large arrays since it creates an intermediate string object.
* **reduce()**:
	+ Pros: Allows for more control over the concatenation process and can be more flexible than `join()`.
	+ Cons: Requires a callback function, which can make the code harder to read and maintain.

**Library Usage**

In this benchmark, no libraries are explicitly used. However, JavaScript's built-in `Array.prototype.join()` and `Array.prototype.reduce()` methods are being tested.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax mentioned in the provided benchmark. The code only uses standard JavaScript syntax.

**Other Considerations**

* **Array Size**: The benchmark uses a large array (`sArr`) with 1000 elements, which can affect the performance of both `join()` and `reduce()`.
* **Separator Character**: In this example, an empty string is used as the separator for `join()`, but other characters (e.g., commas or newline characters) could be used depending on the specific use case.

**Alternatives**

If you're looking for alternative approaches to concatenating strings in JavaScript, here are a few options:

1. **template literals**: Template literals are a more modern way of string interpolation that can be faster than `join()` and `reduce()`.
2. **String formatting functions**: Functions like `sprintf()` or `printf()` from libraries like Moment.js can provide more control over the concatenation process.
3. **Array iteration with for loops**: Using traditional for loops to iterate through the array elements can also be an option, although it may not be as efficient or readable.

In summary, this benchmark provides a simple and informative way to compare the performance of two common JavaScript methods: `join()` and `reduce()`.

Related benchmarks:

Reduce and join in javascript (version: 0)

Comparing performance of: Join vs Reduce

Created: 2 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):