Benchmark: String concatenation vs array join258

Script Preparation code:

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

Tests:

String concatentation
str = "string" + "string" + "string" + "string" + "string" + "string" + "string" + "string" + "string" + "string"
Array join
sArr = ["string", "string", "string", "string", "string", "string", "string", "string", "string", "string"] str = sArr.join("");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String concatentation
Array join

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 explanation of the provided JSON benchmark definition and test cases.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmark that compares two approaches for string concatenation: the traditional approach using the `+` operator, and the array join approach using the `join()` method. The benchmark is designed to measure which approach is faster on a specific device (iPhone running iOS 16.6) using Mobile Safari 16.

**Script Preparation Code**

The script preparation code initializes two variables:
```javascript
var str = "";
var i;
var sArr = [];
```
`str` is initialized as an empty string, and `i` is not used in the benchmark (which might be a mistake?). The array `sArr` is also initialized as an empty array.

**Html Preparation Code**

The html preparation code is null, which means that no HTML-related setup is required for this benchmark.

**Individual Test Cases**

There are two test cases:

1. **String Concatenation**

The benchmark definition for this test case uses the traditional approach of concatenating strings using the `+` operator:
```javascript
str = "string" + "string" + "string" + "string" + "string" + "string" + "string" + "string" + "string" + "string";
```
This approach creates a new string object by concatenating multiple strings using the `+` operator.

2. **Array Join**

The benchmark definition for this test case uses the array join approach, which takes an array of strings and joins them into a single string using the `join()` method:
```javascript
sArr = ["string", "string", "string", "string", "string", "string", "string", "string", "string", "string"];
str = sArr.join("");
```
This approach uses an array to store multiple strings and then joins them into a single string using the `join()` method.

**Pros and Cons of Each Approach**

1. **Traditional Concatenation**
	* Pros:
		+ Easy to understand and implement.
		+ Can be useful for small, short strings.
	* Cons:
		+ Creates multiple intermediate string objects, which can lead to performance issues.
		+ May be slower than the array join approach due to string creation overhead.
2. **Array Join**
	* Pros:
		+ More efficient than traditional concatenation since only one string object is created.
		+ Can handle large numbers of strings more easily.
	* Cons:
		+ Requires an extra step to create the array, which might add overhead.

**Library and Special JS Feature**

Neither test case uses a library or a special JavaScript feature. The `join()` method is a built-in Array prototype method that is supported by most modern browsers.

**Other Considerations**

When choosing between traditional concatenation and array join, consider the size of your strings and the frequency of string concatenation in your codebase. For small strings, traditional concatenation might be sufficient. However, for larger strings or performance-critical code, array join is likely a better choice.

As an alternative to these two approaches, you could also consider using `template literals` (introduced in ECMAScript 2015) for string interpolation:
```javascript
str = `${"string"}${"string"}${"string"}${"string"}${"string"}${"string"}${"string"}${"string"}${"string"}${"string"}${"string"}`;
```
This approach is more concise and expressive than traditional concatenation, but it requires support for template literals in your target browsers.

Keep in mind that the choice of string concatenation approach ultimately depends on the specific requirements of your project and the performance characteristics of your target environment.

Latest run results:

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

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 16_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 16 on iOS 16.6

View result in a separate tab

Test name	Executions per second
String concatentation	7276681.5 Ops/sec
Array join	1883493.2 Ops/sec

Related benchmarks:

String concatenation vs array join258 (version: 0)

Comparing performance of: String concatentation vs Array join

Created: one year ago by: Guest

Jump to the latest result

String concatentation

Array join

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):