Benchmark: TextDecoder 'ascii' vs String.fromCharCodea

Script Preparation code:

var bytes = [84,104,105,115,32,105,115,32,97,32,115,97,109,112,108,101,32,112,97,114,97,103,114,97,112,104,46];
var bufferArray = new Uint16Array(bytes);
var decoder = new TextDecoder('utf8'); // default 'utf-8' or 'utf8'

Tests:

String.fromCharCode
String.fromCharCode.apply(null, bufferArray);
TextDecoder
decoder.decode(bufferArray);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String.fromCharCode
TextDecoder

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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**Benchmark Description**

The benchmark measures the performance difference between two approaches to convert a Uint16Array (a buffer containing 16-bit unsigned integers) to a string:

1. **String.fromCharCode**: This method uses the `apply` method to call the `charCodeAt` function for each element in the array, concatenating the results into a single string.
2. **TextDecoder**: This method uses the `TextDecoder` API to decode the buffer as UTF-8 (or 'utf-8' with a lowercase 'u').

**Options Comparison**

The two approaches have different trade-offs:

* **String.fromCharCode**:
	+ Pros: Simple, widely supported, and efficient for small buffers.
	+ Cons: May be slower for large buffers due to the overhead of concatenating strings in JavaScript.
	+ Additional considerations: This method can lead to issues with character encoding and normalization.
* **TextDecoder**:
	+ Pros: Efficient, accurate, and well-suited for large buffers. It also handles encoding and normalization correctly.
	+ Cons: May require additional setup (e.g., specifying the encoding) and is not supported in older browsers.

**Library**

In this benchmark, a `Uint16Array` is used as a buffer. A Uint16Array is a typed array that represents an array of 16-bit unsigned integers. It's a convenient data structure for working with binary data in JavaScript.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntaxes used in this benchmark. The focus is on the performance comparison between two simple, well-known approaches to converting a buffer to a string.

**Other Alternatives**

If you're interested in exploring other alternatives, here are some options:

* **Array.prototype.join()**: Another way to concatenate strings in an array.
* **Blob**: A binary data type that can be used to represent buffers.
* **Typed arrays with typed constructors**: Depending on the browser support and use case, other typed arrays like Int8Array, Uint32Array, or Float64Array might be suitable alternatives.

In summary, this benchmark provides a simple and insightful comparison of two approaches for converting a buffer to a string in JavaScript. The results can help developers make informed decisions about which method to use depending on their specific requirements and constraints.

Related benchmarks:

TextDecoder 'ascii' vs String.fromCharCodea (version: 0)

Comparing performance of: String.fromCharCode vs TextDecoder

Created: 2 years ago by: Guest

Jump to the latest result

String.fromCharCode

TextDecoder

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):