# Errors optimizing with Closure Compiler (Emscripten) **URL:** \ **Category:** FMOD Engine\ **Tags:** html5\ **Created:** [June 30, 2023, 9:25am UTC](https://qa.fmod.com/t/errors-optimizing-with-closure-compiler-emscripten/20366 "2023-06-30T09:25:08Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![robertmiller1](https://avatars.discourse-cdn.com/v4/letter/r/d2c977/32.png) [@robertmiller1](https://qa.fmod.com/u/robertmiller1)\ **Post date:** [June 30, 2023, 9:25am UTC](https://qa.fmod.com/t/errors-optimizing-with-closure-compiler-emscripten/20366/1 "2023-06-30T09:25:08Z")
Compiling an application using recent Emscripten and FMOD 2.02.15 `upstream/w32/fmod_wasm.a` with the `--closure=1` option to optimize JavaScript I get a lot of errors that seem to originate from FMOD’s JavaScript code: ```auto building:ERROR: Closure compiler run failed: building:ERROR: Application.js:1001:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable contextForCheck is undeclared 1001| contextForCheck = new (window.AudioContext || window.webkitAudioContext)(); ^^^^^^^^^^^^^^^ Application.js:1005:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable retValue is undeclared 1005| retValue = 0; ^^^^^^^^ Application.js:1016:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable infocontext is undeclared 1016| infocontext = new (window.AudioContext || window.webkitAudioContext)(); ^^^^^^^^^^^ Application.js:1020:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable inforate is undeclared 1020| inforate = infocontext.sampleRate; ^^^^^^^^ Application.js:1026:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mInputRegistered is undeclared 1026| mInputRegistered = false; ^^^^^^^^^^^^^^^^ Application.js:1029:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable context is undeclared 1029| context = new (window.AudioContext || window.webkitAudioContext)(); ^^^^^^^ Application.js:1033:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable FMOD_JS_MixFunction is undeclared 1033| FMOD_JS_MixFunction = Module.cwrap("FMOD_JS_MixFunction", "void", ["number"]); ^^^^^^^^^^^^^^^^^^^ Application.js:1037:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable _as_script_node is undeclared 1037| _as_script_node = context.createScriptProcessor($1, 0, $0); ^^^^^^^^^^^^^^^ Application.js:1040:38: ERROR - [JSC_UNDEFINED_VARIABLE] variable OutputWebAudio_resumeAudio is undeclared 1040| window.addEventListener("touchend", OutputWebAudio_resumeAudio, false); ^^^^^^^^^^^^^^^^^^^^^^^^^^ Application.js:1054:3: ERROR - [JSC_UNDEFINED_VARIABLE] variable _as_output_buffer is undeclared 1054| _as_output_buffer = audioProcessingEvent.outputBuffer; ^^^^^^^^^^^^^^^^^ Application.js:1087:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mWorkletNode is undeclared 1087| mWorkletNode = null; ^^^^^^^^^^^^ Application.js:1088:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mModulePolling is undeclared 1088| mModulePolling = false; ^^^^^^^^^^^^^^ Application.js:1089:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mModuleLoading is undeclared 1089| mModuleLoading = false; ^^^^^^^^^^^^^^ Application.js:1090:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mStartInterval is undeclared 1090| mStartInterval = null; ^^^^^^^^^^^^^^ Application.js:1091:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mStopInterval is undeclared 1091| mStopInterval = null; ^^^^^^^^^^^^^ Application.js:1092:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mSuspendInterval is undeclared 1092| mSuspendInterval = null; ^^^^^^^^^^^^^^^^ Application.js:1093:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mResumeInterval is undeclared 1093| mResumeInterval = null; ^^^^^^^^^^^^^^^ Application.js:1094:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mWorkletNodeConnected is undeclared 1094| mWorkletNodeConnected = false; ^^^^^^^^^^^^^^^^^^^^^ Application.js:1096:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mContext is undeclared 1096| mContext = new (window.AudioContext || window.webkitAudioContext)(); ^^^^^^^^ Application.js:1106:3: ERROR - [JSC_UNDEFINED_VARIABLE] variable mAddModuleRef is undeclared 1106| mAddModuleRef = 0; ^^^^^^^^^^^^^ Application.js:1114:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable FMOD_JS_MixerSlowpathFunction is undeclared 1114| FMOD_JS_MixerSlowpathFunction = Module.cwrap("FMOD_JS_MixerSlowpathFunction", "void", []); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Application.js:1115:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable FMOD_JS_MixerFastpathFunction is undeclared 1115| FMOD_JS_MixerFastpathFunction = Module.cwrap("FMOD_JS_MixerFastpathFunction", "void", ["number"]); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Application.js:1119:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mSpeakerChannelCount is undeclared 1119| mSpeakerChannelCount = $0; ^^^^^^^^^^^^^^^^^^^^ Application.js:1121:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mUrl is undeclared 1121| mUrl = null; ^^^^ Application.js:1122:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mOutputData is undeclared 1122| mOutputData = null; ^^^^^^^^^^^ Application.js:1123:2: ERROR - [JSC_UNDEFINED_VARIABLE] variable mSharedArrayBuffers is undeclared 1123| mSharedArrayBuffers = false; ^^^^^^^^^^^^^^^^^^^ Application.js:1146:38: ERROR - [JSC_UNDEFINED_VARIABLE] variable OutputAudioWorklet_resumeAudio is undeclared 1146| window.addEventListener("touchend", OutputAudioWorklet_resumeAudio, false); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Application.js:1180:19: ERROR - [JSC_UNDEFINED_VARIABLE] variable waitForAudioWorklet is undeclared 1180| mStartInterval = waitForAudioWorklet(function() { ^^^^^^^^^^^^^^^^^^^ 28 error(s), 0 warning(s) ``` I think these errors stem from missing `var` keywords. As this code is integrated into the `.a` library file I can’t change it. Can this be fixed? ---
**Author:** ![Leah\_FMOD](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/leah_fmod/32/3685_2.png) [@Leah\_FMOD](https://qa.fmod.com/u/Leah_FMOD)\ **Post date:** [July 3, 2023, 11:21pm UTC](https://qa.fmod.com/t/errors-optimizing-with-closure-compiler-emscripten/20366/2 "2023-07-03T23:21:50Z")
Hi, This appears to be caused by a known issue wherein FMOD JS doesn’t respect strict mode. Unfortunately, all I can recommend is that you not use closure compiler optimizations, and if you’re not already, consider using either the `-Os` or `-Oz` optimization flags for reduced code size.