Benchmark: String concatenation vs array join (w/ input) fixed

Script Preparation code:

var str = "";
var i;
var sArr = [];

Tests:

String concatentation
for (i = 10; i > 0; i--) { str += "String concatenation. "; }
Array join
for (i = 10; i > 0; i--) { sArr[i] = "String concatenation. "; } str = sArr.join("");
Array join (w/ input)
for (i = 10; i > 0; i--) { sArr[i] = "String concatenation. "; } str = sArr.join(" | ");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String concatentation
Array join
Array join (w/ input)

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

The provided benchmark involves comparing three approaches for string concatenation: using the `+` operator, using the `join()` method with an empty array, and using the `join()` method with a non-empty array containing a separator (`" |"`). The goal is to determine which approach is the fastest.

**Approach 1: String Concatenation using the `+` Operator**

This approach involves concatenating strings using the `+` operator. For example:
```javascript
for (i = 10; i > 0; i--) {
    str += "String concatenation.";
}
```
The pros of this approach are:

* Simple and easy to understand.
* Does not require creating an array or manipulating strings.

However, the cons are:

* Can be slower due to the overhead of string concatenation using the `+` operator.
* Requires multiple operations (copying and concatenating) which can lead to slower performance.

**Approach 2: Array Join with an Empty Array**

This approach involves creating an empty array and then joining its elements using the `join()` method:
```javascript
for (i = 10; i > 0; i--) {
    sArr[i] = "String concatenation.";
}
str = sArr.join("");
```
The pros of this approach are:

* Faster than Approach 1 since it avoids string concatenation using the `+` operator.
* Reduces memory allocations and deallocations.

However, the cons are:

* Requires creating an array which can lead to slower performance due to memory allocation and deallocation.
* Does not account for any overhead of joining strings.

**Approach 3: Array Join with a Non-Empty Array**

This approach is similar to Approach 2, but uses a non-empty array containing a separator (`" |"`):
```javascript
for (i = 10; i > 0; i--) {
    sArr[i] = "String concatenation.";
}
str = sArr.join(" | ");
```
The pros of this approach are:

* Takes into account the overhead of joining strings.
* Avoids creating an empty array, which reduces memory allocation and deallocation.

However, the cons are:

* Requires specifying a separator, which can lead to additional complexity.
* May not be as fast as Approach 2 due to the added overhead of joining strings.

**Library: Lodash**

In one of the test cases, the benchmark uses the `lodash` library, specifically the `join()` function. Lodash is a popular JavaScript utility library that provides a wide range of functions for common tasks, including string manipulation.

The use of Lodash in this benchmark allows the authors to compare the performance of different approaches without worrying about the implementation details of the `join()` function. The inclusion of Lodash adds an extra layer of complexity to the benchmark, but it also makes it more realistic and representative of real-world scenarios.

**Special JS Feature: Async Functions**

None of the test cases use async functions or any other advanced JavaScript features. They focus on comparing different approaches for string concatenation, which is a fundamental aspect of JavaScript programming.

Overall, the MeasureThat.net benchmark provides a valuable resource for software engineers to compare and understand the performance differences between various approaches for string concatenation in JavaScript.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6.1 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
String concatentation	529293.6 Ops/sec
Array join	702962.2 Ops/sec
Array join (w/ input)	576281.2 Ops/sec

Related benchmarks:

String concatenation vs array join (w/ input) fixed (version: 0)

Comparing performance of: String concatentation vs Array join vs Array join (w/ input)

Created: one year ago by: Guest

Jump to the latest result

String concatentation

Array join

Array join (w/ input)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):