2020.3.48 WebGL build error

[BelieveXiaoShuai]

Version: 3.1.4
Unity Version: 2020.6.48
Platform: WebGL
Build Error:Failed process stderr log:
emcc: warning: cannot represent a NaN literal '0x237558f35b0' with custom bit pattern in NaN-canonicalizing JS engines (e.g. Firefox and Safari) without erasing bits!
in %144 = select i1 %.0182.off0, double 0xFFF8000000000000, double 0x7FF8000000000000 in _ZNK17double_conversion23StringToDoubleConverter12StringToIeeeIPKcEEdT_ibPi()

JS optimizer error:
Unexpected token: keyword (const) (line: 2747, col: 19, pos: 106831)

================================

}

var uLipSync={unityCsharpCallback:null,resumeEventNames:["keydown","mousedown","touchstart"],userEventCallback:function () {
Module.dynCall_v(uLipSync.unityCsharpCallback);
for (const ev of uLipSync.resumeEventNames) {
^

D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:282
throw new JS_Parse_Error(message, line, col, pos);
^
Error
at new JS_Parse_Error (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:260:22)
at js_error (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:282:15)
at croak (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:752:17)
at token_error (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:760:17)
at unexpected (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:766:17)
at D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:1131:17
at maybe_unary (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:1220:27)
at expr_ops (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:1247:32)
at maybe_conditional (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:1251:28)
at maybe_assign (D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:1275:28)
at D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\eliminator\node_modules\uglify-js\lib\parse-js.js:1289:28
ERROR:root:'D:/Unity/2020.3.48f1/Editor/Data\Tools\nodejs\node.exe --stack_size=8192 --max-old-space-size=4096 D:\Unity\2020.3.48f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\tools\js-optimizer.js C:\Users\asus\AppData\Local\Temp\tmp_selij\build.bc.o.js.pp.js.mem.js noPrintMetadata AJSDCE minifyWhitespace' failed

[hecomi]

In Unity 2020.X, the Emscripten version is outdated, and the const keyword on the JavaScript side cannot be used, so unfortunately, it won’t work. It should function properly with Unity 2021.2 or later.