Run results for: TextDecoder vs String.fromCharCode vs String.fromCodePoint

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:124.0) Gecko/20100101 Firefox/124.0

Browser: Firefox 124

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
TextDecoder on Uint8Array	21103.3 Ops/sec
String.fromCharCode on Uint8Array	7943.6 Ops/sec
String.fromCharCode on Array	12561.7 Ops/sec
String.fromCodePoint on Uint8Array	7349.1 Ops/sec
String.fromCodePoint on Array	9588.3 Ops/sec

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];
})();

Tests:

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

Run results for: TextDecoder vs String.fromCharCode vs String.fromCodePoint

TextDecoder on Uint8Array

String.fromCharCode on Uint8Array

String.fromCharCode on Array

String.fromCodePoint on Uint8Array

String.fromCodePoint on Array