Benchmark: join vs reduce - MeasureThat.net

Script Preparation code:

var strings = [];
for (var i=0; i<1000; i++) {
  strings[i] = ""+i+i;
}

Tests:

reduce
let ret = strings.reduce((acc, currentValue) => { if (currentValue) { acc += `${currentValue};`; } return acc; }, "");
join
let ret = strings.join(";")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reduce
join

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

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

**Benchmark Purpose:**
The purpose of this benchmark is to compare the performance of two string concatenation methods in JavaScript:

1. `join()`: which uses the `+` operator to concatenate strings with a separator (in this case, a semicolon).
2. `reduce()`: which accumulates values by applying a callback function to each element.

**Options Compared:**

* `join()`: This method concatenates all elements in an array and returns the resulting string. It uses the `+` operator to concatenate strings with a separator.
* `reduce()`: This method applies a callback function to each element of an array, accumulating a value. In this case, the callback function simply appends the current value to the accumulator.

**Pros and Cons:**

* **join()**: Pros:
	+ Concise and easy to read.
	+ Can be efficient for concatenating large numbers of strings with a separator.
* Cons:
	+ Can lead to performance issues if the number of strings is very large, due to the overhead of repeated `+` operations.
* `reduce()``: Pros:
	+ More flexible than `join()`, as it allows you to customize the callback function.
	+ Can be efficient for accumulating values from an array.
* Cons:
	+ Requires more code and can be less readable than `join()`.
	+ May incur performance overhead due to the creation of a new accumulator value.

**Library Used:**
None, as this is a built-in JavaScript method.

**Special JS Feature/Syntax:**
The benchmark uses modern JavaScript features, such as:

* Template literals (`strings[i] = ""+i+i;`)
* Arrow functions (`(acc, currentValue) => { ... }`)

These features are supported by most modern browsers and JavaScript engines.

**Other Alternatives:**

* `concat()`: This method concatenates all elements in an array and returns the resulting string. It is similar to `join()`, but uses the `concat()` method instead.
* Other string concatenation methods, such as using a `for` loop with a temporary variable, can also be used.

The benchmark result shows that `join()` performs better than `reduce()` in this specific test case, likely due to the overhead of repeated `+` operations in `reduce()`.

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:121.0) Gecko/20100101 Firefox/121.0

Browser/OS: Firefox 121 on Windows

View result in a separate tab

Test name	Executions per second
reduce	38736.1 Ops/sec
join	68984.7 Ops/sec

Related benchmarks:

join vs reduce (version: 0)

Comparing performance of: reduce vs join

Created: one year ago by: Guest

Jump to the latest result

reduce

join

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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