Benchmark: Encode byte string test (string concatenation vs. map join)

Script Preparation code:

var text = '鉴于对人类家庭所有成员的固有尊严及其平等的和不移的权利的承认，乃是世界自由、正义与和平的基础';
var uint8Array = new TextEncoder().encode(text);

Tests:

String concatenation (from Uint8Array)
let byteStr = ''; uint8Array.forEach(i => { byteStr += String.fromCharCode(i); });
Array map join
let byteStr = new Array(uint8Array).map(i => String.fromCharCode(i)).join('');
String concatenation (from Uint8Array converted to Array)
let byteStr = ''; new Array(uint8Array).forEach(i => { byteStr += String.fromCharCode(i); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String concatenation (from Uint8Array)
Array map join
String concatenation (from Uint8Array converted to Array)

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Windows

View result in a separate tab

Test name	Executions per second
String concatenation (from Uint8Array)	620620.4 Ops/sec
Array map join	475546.2 Ops/sec
String concatenation (from Uint8Array converted to Array)	491062.5 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 benchmark and analyze what is being tested.

**Benchmark Definition:**

The benchmark tests the performance of three different approaches to concatenate a byte string:

1. **String concatenation using `forEach`**: This approach uses the `forEach` method to iterate over the `uint8Array` and convert each element to a string using `String.fromCharCode`. The strings are then concatenated using the `+=` operator.
2. **Array map join**: This approach converts the `uint8Array` to an array using `new Array(uint8Array)`, maps each element to a string using `map`, and then joins the strings together using the `join` method.
3. **String concatenation using `forEach` converted to array**: This is similar to the first approach, but instead of using `uint8Array` directly, it's converted to an array first.

**Pros and Cons:**

1. **String concatenation using `forEach`**:
	* Pros: Simple and easy to read.
	* Cons: Can be slow due to the overhead of creating temporary strings.
2. **Array map join**:
	* Pros: More efficient than string concatenation, as it avoids creating temporary strings.
	* Cons: Requires more memory to store the intermediate array.
3. **String concatenation using `forEach` converted to array**:
	* Pros: Avoids the overhead of creating temporary strings like in the first approach.
	* Cons: Requires additional memory to store the intermediate array.

**Library and Special JS Feature:**

None of the approaches use any specific libraries or special JavaScript features beyond standard ES6 syntax.

**Considerations:**

The benchmark is likely designed to test the performance of each approach in a scenario where the input data is known (a fixed-size byte string). The results are likely intended to show which approach is faster for encoding byte strings, with potential implications for optimizing code that performs similar tasks.

**Alternatives:**

Other approaches to concatenate byte strings might include:

* Using a buffer or Uint8Array constructor's `toString()` method.
* Utilizing WebAssembly (WASM) and its optimized string handling functions.
* Leveraging native libraries like ICU (International Components for Unicode).

However, the provided benchmark focuses on the three approaches listed above, so it's likely that these alternatives are not being tested.

Overall, this benchmark provides a simple yet informative test of performance differences between three common approaches to concatenating byte strings in JavaScript.

Related benchmarks:

Encode byte string test (string concatenation vs. map join) (version: 7)

Encode byte string

Comparing performance of: String concatenation (from Uint8Array) vs Array map join vs String concatenation (from Uint8Array converted to Array)

Created: 3 years ago by: Registered User

Jump to the latest result

String concatenation (from Uint8Array)

Array map join

String concatenation (from Uint8Array converted to Array)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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