Benchmark: TextDecoder vs String.fromCharCode vs String.fromCodePoint

Script Preparation code:

var [testDecode, testFCCodeBuf, testFCCodeArr, testFCPointBuf, testFCPointArr] = (function(){
  "use strict";
  var bytesArray = [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 Uint8Array(bytesArray);
  var decoder = new TextDecoder(); // default 'utf-8' or 'utf8'
  var {fromCharCode, fromCodePoint} = String;
  var retStr = "";
  self.getRetStr = function() {return retStr};
  
  function testDecode() {
  	for (var i=0; i < 256; i=i+1|0) retStr = "" + decoder.decode(bufferArray);
  }
  function testFCCodeBuf() {
  	for (var i=0; i < 256; i=i+1|0) retStr = "" + fromCharCode.apply(null, bufferArray);
  }
  function testFCCodeArr() {
  	for (var i=0; i < 256; i=i+1|0) retStr = "" + fromCharCode.apply(null, bytesArray);
  }
  function testFCPointBuf() {
  	for (var i=0; i < 256; i=i+1|0) retStr = "" + fromCodePoint.apply(null, bufferArray);
  }
  function testFCPointArr() {
  	for (var i=0; i < 256; i=i+1|0) retStr = "" + fromCodePoint.apply(null, bytesArray);
  }
  
  return [testDecode, testFCCodeBuf, testFCCodeArr, testFCPointBuf, testFCPointArr];
})();

​x
 
var [testDecode, testFCCodeBuf, testFCCodeArr, testFCPointBuf, testFCPointArr] = (function(){  "use strict";  var bytesArray = [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 Uint8Array(bytesArray);  var decoder = new TextDecoder(); // default 'utf-8' or 'utf8'  var {fromCharCode, fromCodePoint} = String;  var retStr = "";  self.getRetStr = function() {return retStr};    function testDecode() {    for (var i=0; i < 256; i=i+1|0) retStr = "" + decoder.decode(bufferArray);  }  function testFCCodeBuf() {    for (var i=0; i < 256; i=i+1|0) retStr = "" + fromCharCode.apply(null, bufferArray);  }  function testFCCodeArr() {    for (var i=0; i < 256; i=i+1|0) retStr = "" + fromCharCode.apply(null, bytesArray);  }  function testFCPointBuf() {    for (var i=0; i < 256; i=i+1|0) retStr = "" + fromCodePoint.apply(null, bufferArray);  }  function testFCPointArr() {    for (var i=0; i < 256; i=i+1|0) retStr = "" + fromCodePoint.apply(null, bytesArray);  }    return [testDecode, testFCCodeBuf, testFCCodeArr, testFCPointBuf, testFCPointArr];})();​

Tests:

TextDecoder on Uint8Array
testDecode();
testDecode();
String.fromCharCode on Uint8Array
testFCCodeBuf();
testFCCodeBuf();
String.fromCharCode on Array
testFCCodeArr();
testFCCodeArr();
String.fromCodePoint on Uint8Array
testFCPointBuf();
testFCPointBuf();
String.fromCodePoint on Array
testFCPointArr();
testFCPointArr();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
TextDecoder on Uint8Array
String.fromCharCode on Uint8Array
String.fromCharCode on Array
String.fromCodePoint on Uint8Array
String.fromCodePoint on Array

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0

Browser/OS: Firefox 135 on Linux

View result in a separate tab

Test name	Executions per second
TextDecoder on Uint8Array	29480.1 Ops/sec
String.fromCharCode on Uint8Array	15879.3 Ops/sec
String.fromCharCode on Array	57867.5 Ops/sec
String.fromCodePoint on Uint8Array	12409.2 Ops/sec
String.fromCodePoint on Array	27346.9 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

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

Benchmark Overview

The benchmark compares the performance of three different ways to convert between code points and Unicode strings:

TextDecoder on Uint8Array
String.fromCharCode on Uint8Array
String.fromCharCode on an array

These conversions are essential in JavaScript, as they can be used to decode binary data, such as images or audio files.

Options Compared

The benchmark compares the performance of each option across two scenarios:

Converting a fixed-size array of code points (i.e., ASCII characters) from Uint8Array to a string.
Converting an array of code points from Uint8Array to a string (for Unicode characters).

Pros and Cons

Here's a brief summary of the pros and cons of each option:

TextDecoder on Uint8Array
- Pros: Efficient for decoding binary data, handles large inputs well.
- Cons: May require additional setup for Unicode handling, can be slower than String.fromCharCode for small inputs.
String.fromCharCode on Uint8Array
- Pros: Simple, fast, and efficient for small inputs.
- Cons: Can be slower for large inputs due to repeated string concatenation, may not handle Unicode characters correctly without additional setup.
String.fromCharCode on Array
- Pros: Similar performance characteristics to String.fromCharCode on Uint8Array, handles Unicode characters correctly.
- Cons: May require more memory than using TextDecoder, can be slower for very large inputs.

Library and Purpose

In this benchmark, the following libraries are used:

TextDecoder: A built-in JavaScript library for decoding binary data into strings.
String.fromCharCode (and its array equivalent): Built-in JavaScript functions for converting code points to Unicode characters.

Special JS Feature or Syntax

None of the tested options rely on special JavaScript features or syntax beyond what's covered in the ECMAScript standard.

Other Alternatives

If you need to optimize these conversions, consider using:

Buffer: For decoding binary data into strings, as it provides a more efficient way to handle large inputs.
Web Workers: To parallelize the computation and take advantage of multi-core processors, especially for very large input sizes.

In conclusion, this benchmark helps you understand the performance differences between TextDecoder, String.fromCharCode, and its array equivalent when converting code points to Unicode strings from a fixed-size array or Uint8Array. The choice of option depends on your specific use case and performance requirements.

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark compares the performance of three different ways to convert between code points and Unicode strings:

1. `TextDecoder` on `Uint8Array`
2. `String.fromCharCode` on `Uint8Array`
3. `String.fromCharCode` on an array

These conversions are essential in JavaScript, as they can be used to decode binary data, such as images or audio files.

**Options Compared**

The benchmark compares the performance of each option across two scenarios:

* Converting a fixed-size array of code points (i.e., ASCII characters) from `Uint8Array` to a string.
* Converting an array of code points from `Uint8Array` to a string (for Unicode characters).

**Pros and Cons**

Here's a brief summary of the pros and cons of each option:

1. **TextDecoder on Uint8Array**
	* Pros: Efficient for decoding binary data, handles large inputs well.
	* Cons: May require additional setup for Unicode handling, can be slower than `String.fromCharCode` for small inputs.
2. **String.fromCharCode on Uint8Array**
	* Pros: Simple, fast, and efficient for small inputs.
	* Cons: Can be slower for large inputs due to repeated string concatenation, may not handle Unicode characters correctly without additional setup.
3. **String.fromCharCode on Array**
	* Pros: Similar performance characteristics to `String.fromCharCode` on `Uint8Array`, handles Unicode characters correctly.
	* Cons: May require more memory than using `TextDecoder`, can be slower for very large inputs.

**Library and Purpose**

In this benchmark, the following libraries are used:

1. `TextDecoder`: A built-in JavaScript library for decoding binary data into strings.
2. `String.fromCharCode` (and its array equivalent): Built-in JavaScript functions for converting code points to Unicode characters.

**Special JS Feature or Syntax**

None of the tested options rely on special JavaScript features or syntax beyond what's covered in the ECMAScript standard.

**Other Alternatives**

If you need to optimize these conversions, consider using:

1. **Buffer**: For decoding binary data into strings, as it provides a more efficient way to handle large inputs.
2. **Web Workers**: To parallelize the computation and take advantage of multi-core processors, especially for very large input sizes.

In conclusion, this benchmark helps you understand the performance differences between `TextDecoder`, `String.fromCharCode`, and its array equivalent when converting code points to Unicode strings from a fixed-size array or `Uint8Array`. The choice of option depends on your specific use case and performance requirements.

Related benchmarks:

TextDecoder vs String.fromCharCode vs String.fromCodePoint (version: 0)

Comparing performance of: TextDecoder on Uint8Array vs String.fromCharCode on Uint8Array vs String.fromCharCode on Array vs String.fromCodePoint on Uint8Array vs String.fromCodePoint on Array

Created: one year ago by: Guest

Jump to the latest result

TextDecoder on Uint8Array

String.fromCharCode on Uint8Array

String.fromCharCode on Array

String.fromCodePoint on Uint8Array

String.fromCodePoint on Array

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):