Benchmark: string concatenation vs string array

Script Preparation code:

var str = '';
var strArr = new Array(10000);

Tests:

String concatenation
for (let i = 0; i < 10000; i++) { str += 'new string'; }
String array
for (let i = 0; i < 10000; i++) { strArr[i] = 'new string'; } strArr.join();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String concatenation
String array

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down what's being tested in the provided benchmark.

**Benchmark Definition JSON**

The benchmark is comparing two approaches to concatenate strings:

1. **String Concatenation**: Using the `+` operator to append strings together.
2. **String Array**: Using an array to store individual string elements and then joining them using the `join()` method.

**Options Compared**

The two options being compared are:

* String concatenation: `str += 'new string';`
* String array with `join()`: `strArr[i] = 'new string';` followed by `strArr.join();`

**Pros and Cons of Each Approach**

1. **String Concatenation**
	* Pros:
		+ Simple and intuitive to implement.
		+ Can be faster for small strings or when concatenating only a few elements.
	* Cons:
		+ Inefficient for large numbers of concatenations, as it creates a new string object on each iteration.
		+ Can lead to memory issues if not managed properly (e.g., using `str += '...'` instead of `let str = ''; str += '...';`).
2. **String Array with `join()`
	* Pros:
		+ More efficient for large numbers of concatenations, as it avoids creating new string objects on each iteration.
		+ Easier to manage memory, as the array can be garbage collected when no longer needed.
	* Cons:
		+ Requires more overhead due to the need to create an array and then join its elements.
		+ Can be slower for very small strings or only one element.

**Library Used**

None explicitly mentioned. However, assuming a modern JavaScript environment, the `join()` method is likely implemented in terms of V8's (Chrome's) internal string implementation, which uses a variety of optimized algorithms to concatenate strings efficiently.

**Special JS Feature/Syntax**

None explicitly used or mentioned. The benchmark only focuses on comparing two string concatenation approaches.

**Other Alternatives**

For larger-scale string concatenations, other alternatives might include:

* Using `StringBuilder` (if available in the JavaScript environment) for a more efficient and modern way to build strings.
* Utilizing native WebAssembly or other performance-critical libraries optimized for string manipulation.
* Implementing custom string concatenation algorithms using low-level memory management and bitwise operations.

Keep in mind that these alternatives are typically only necessary for very high-performance applications, and the trade-offs between ease of use, maintainability, and raw performance might favor the simple `+` operator approach for most use cases.

Related benchmarks:

string concatenation vs string array (version: 0)

Comparing performance of: String concatenation vs String array

Created: 3 years ago by: Registered User

Jump to the latest result

String concatenation

String array

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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