emscripten-core · juj · Sep 22, 2025 · Oct 1, 2025 · Oct 1, 2025 · Oct 1, 2025
diff --git a/src/lib/libstrings.js b/src/lib/libstrings.js
@@ -9,11 +9,13 @@
 #endif
 
 addToLibrary({
+  // In -sAUDIO_WORKLET builds, TextDecoder will not exist in AudioWorkletGlobalScope,
+  // so we cannot try to unconditionally initialize it in that build mode.
+#if TEXTDECODER == 2 && !AUDIO_WORKLET
   // TextDecoder constructor defaults to UTF-8
-#if TEXTDECODER == 2
   $UTF8Decoder: "new TextDecoder()",
 #else
-  $UTF8Decoder: "globalThis.TextDecoder ? new TextDecoder() : undefined",
+  $UTF8Decoder: "globalThis.TextDecoder && new TextDecoder()",
 #endif
 
   $findStringEnd: (heapOrArray, idx, maxBytesToRead, ignoreNul) => {

diff --git a/src/lib/libwebaudio.js b/src/lib/libwebaudio.js
@@ -1,8 +1,8 @@
 #if AUDIO_WORKLET && !WASM_WORKERS
-#error "Building with -sAUDIO_WORKLET also requires enabling -sWASM_WORKERS!"
+#error "Building with -sAUDIO_WORKLET also requires enabling -sWASM_WORKERS"
 #endif
 #if AUDIO_WORKLET && TEXTDECODER == 2
-#error "-sAUDIO_WORKLET does not support -sTEXTDECODER=2 since TextDecoder is not available in AudioWorkletGlobalScope! Use e.g. -sTEXTDECODER=1 when building with -sAUDIO_WORKLET"
+#warning "-sAUDIO_WORKLET does not support -sTEXTDECODER=2 since TextDecoder is not available in AudioWorkletGlobalScope. Text decoding will be unavailable in Audio Worklets. If you need string marshalling in Audio Worklets, build with -sTEXTDECODER=1."
 #endif
 #if AUDIO_WORKLET && SINGLE_FILE
 #error "-sAUDIO_WORKLET does not support -sSINGLE_FILE"

diff --git a/test/codesize/audio_worklet_wasm.expected.js b/test/codesize/audio_worklet_wasm.expected.js
@@ -111,7 +111,7 @@ var L = [], M = a => {
 }, Q = (a, b, e, d) => {
     b = P[b];
     P[a].connect(b.destination || b, e, d);
-}, P = {}, R = 0, S = globalThis.TextDecoder ? new TextDecoder : void 0, T = (a = 0) => {
+}, P = {}, R = 0, S = globalThis.TextDecoder && new TextDecoder, T = (a = 0) => {
     for (var b = J, e = a, d = e + void 0; b[e] && !(e >= d); ) ++e;
     if (16 < e - a && b.buffer && S) return S.decode(b.slice(a, e));
     for (d = ""; a < e; ) {

diff --git a/test/codesize/test_codesize_cxx_ctors1.json b/test/codesize/test_codesize_cxx_ctors1.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 19676,
-  "a.out.js.gz": 8151,
+  "a.out.js": 19670,
+  "a.out.js.gz": 8152,
   "a.out.nodebug.wasm": 129509,
   "a.out.nodebug.wasm.gz": 49243,
-  "total": 149185,
-  "total_gz": 57394,
+  "total": 149179,
+  "total_gz": 57395,
   "sent": [
     "__cxa_throw",
     "_abort_js",

diff --git a/test/codesize/test_codesize_cxx_ctors2.json b/test/codesize/test_codesize_cxx_ctors2.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 19653,
-  "a.out.js.gz": 8138,
+  "a.out.js": 19647,
+  "a.out.js.gz": 8139,
   "a.out.nodebug.wasm": 128936,
   "a.out.nodebug.wasm.gz": 48884,
-  "total": 148589,
-  "total_gz": 57022,
+  "total": 148583,
+  "total_gz": 57023,
   "sent": [
     "__cxa_throw",
     "_abort_js",

diff --git a/test/codesize/test_codesize_cxx_except.json b/test/codesize/test_codesize_cxx_except.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 23331,
-  "a.out.js.gz": 9129,
+  "a.out.js": 23325,
+  "a.out.js.gz": 9128,
   "a.out.nodebug.wasm": 171271,
   "a.out.nodebug.wasm.gz": 57338,
-  "total": 194602,
-  "total_gz": 66467,
+  "total": 194596,
+  "total_gz": 66466,
   "sent": [
     "__cxa_begin_catch",
     "__cxa_end_catch",

diff --git a/test/codesize/test_codesize_cxx_except_wasm.json b/test/codesize/test_codesize_cxx_except_wasm.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 19561,
-  "a.out.js.gz": 8098,
+  "a.out.js": 19555,
+  "a.out.js.gz": 8099,
   "a.out.nodebug.wasm": 144630,
   "a.out.nodebug.wasm.gz": 54894,
-  "total": 164191,
-  "total_gz": 62992,
+  "total": 164185,
+  "total_gz": 62993,
   "sent": [
     "_abort_js",
     "_tzset_js",

diff --git a/test/codesize/test_codesize_cxx_except_wasm_legacy.json b/test/codesize/test_codesize_cxx_except_wasm_legacy.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 19561,
-  "a.out.js.gz": 8098,
+  "a.out.js": 19555,
+  "a.out.js.gz": 8099,
   "a.out.nodebug.wasm": 142219,
   "a.out.nodebug.wasm.gz": 54358,
-  "total": 161780,
-  "total_gz": 62456,
+  "total": 161774,
+  "total_gz": 62457,
   "sent": [
     "_abort_js",
     "_tzset_js",

diff --git a/test/codesize/test_codesize_cxx_mangle.json b/test/codesize/test_codesize_cxx_mangle.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 23381,
-  "a.out.js.gz": 9149,
+  "a.out.js": 23375,
+  "a.out.js.gz": 9148,
   "a.out.nodebug.wasm": 235312,
-  "a.out.nodebug.wasm.gz": 78933,
-  "total": 258693,
-  "total_gz": 88082,
+  "a.out.nodebug.wasm.gz": 78935,
+  "total": 258687,
+  "total_gz": 88083,
   "sent": [
     "__cxa_begin_catch",
     "__cxa_end_catch",

diff --git a/test/codesize/test_codesize_cxx_noexcept.json b/test/codesize/test_codesize_cxx_noexcept.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 19676,
-  "a.out.js.gz": 8151,
+  "a.out.js": 19670,
+  "a.out.js.gz": 8152,
   "a.out.nodebug.wasm": 131926,
   "a.out.nodebug.wasm.gz": 50238,
-  "total": 151602,
-  "total_gz": 58389,
+  "total": 151596,
+  "total_gz": 58390,
   "sent": [
     "__cxa_throw",
     "_abort_js",

diff --git a/test/codesize/test_codesize_cxx_wasmfs.json b/test/codesize/test_codesize_cxx_wasmfs.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 7065,
-  "a.out.js.gz": 3329,
+  "a.out.js": 7059,
+  "a.out.js.gz": 3330,
   "a.out.nodebug.wasm": 169797,
   "a.out.nodebug.wasm.gz": 63087,
-  "total": 176862,
-  "total_gz": 66416,
+  "total": 176856,
+  "total_gz": 66417,
   "sent": [
     "__cxa_throw",
     "_abort_js",

diff --git a/test/codesize/test_codesize_file_preload.expected.js b/test/codesize/test_codesize_file_preload.expected.js
@@ -666,7 +666,7 @@ var PATH_FS = {
   }
 };
 
-var UTF8Decoder = globalThis.TextDecoder ? new TextDecoder : undefined;
+var UTF8Decoder = globalThis.TextDecoder && new TextDecoder;
 
 var findStringEnd = (heapOrArray, idx, maxBytesToRead, ignoreNul) => {
   var maxIdx = idx + maxBytesToRead;

diff --git a/test/codesize/test_codesize_file_preload.json b/test/codesize/test_codesize_file_preload.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 22479,
-  "a.out.js.gz": 9348,
+  "a.out.js": 22473,
+  "a.out.js.gz": 9349,
   "a.out.nodebug.wasm": 1681,
   "a.out.nodebug.wasm.gz": 960,
-  "total": 24160,
-  "total_gz": 10308,
+  "total": 24154,
+  "total_gz": 10309,
   "sent": [
     "a (fd_write)"
   ],

diff --git a/test/codesize/test_codesize_files_js_fs.json b/test/codesize/test_codesize_files_js_fs.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 18279,
-  "a.out.js.gz": 7466,
+  "a.out.js": 18273,
+  "a.out.js.gz": 7462,
   "a.out.nodebug.wasm": 381,
   "a.out.nodebug.wasm.gz": 260,
-  "total": 18660,
-  "total_gz": 7726,
+  "total": 18654,
+  "total_gz": 7722,
   "sent": [
     "a (fd_write)",
     "b (fd_read)",

diff --git a/test/codesize/test_codesize_files_wasmfs.json b/test/codesize/test_codesize_files_wasmfs.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 5471,
-  "a.out.js.gz": 2579,
-  "a.out.nodebug.wasm": 50235,
-  "a.out.nodebug.wasm.gz": 18098,
-  "total": 55706,
-  "total_gz": 20677,
+  "a.out.js": 5465,
+  "a.out.js.gz": 2576,
+  "a.out.nodebug.wasm": 50231,
+  "a.out.nodebug.wasm.gz": 18094,
+  "total": 55696,
+  "total_gz": 20670,
   "sent": [
     "a (emscripten_date_now)",
     "b (emscripten_err)",

diff --git a/test/codesize/test_codesize_hello_O0.json b/test/codesize/test_codesize_hello_O0.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 23206,
-  "a.out.js.gz": 8525,
+  "a.out.js": 23198,
+  "a.out.js.gz": 8524,
   "a.out.nodebug.wasm": 15127,
   "a.out.nodebug.wasm.gz": 7450,
-  "total": 38333,
-  "total_gz": 15975,
+  "total": 38325,
+  "total_gz": 15974,
   "sent": [
     "fd_write"
   ],

diff --git a/test/codesize/test_codesize_hello_O1.json b/test/codesize/test_codesize_hello_O1.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 6353,
-  "a.out.js.gz": 2462,
+  "a.out.js": 6345,
+  "a.out.js.gz": 2460,
   "a.out.nodebug.wasm": 2675,
   "a.out.nodebug.wasm.gz": 1491,
-  "total": 9028,
-  "total_gz": 3953,
+  "total": 9020,
+  "total_gz": 3951,
   "sent": [
     "fd_write"
   ],

diff --git a/test/codesize/test_codesize_hello_O2.json b/test/codesize/test_codesize_hello_O2.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 4325,
-  "a.out.js.gz": 2132,
+  "a.out.js": 4319,
+  "a.out.js.gz": 2131,
   "a.out.nodebug.wasm": 1927,
   "a.out.nodebug.wasm.gz": 1138,
-  "total": 6252,
-  "total_gz": 3270,
+  "total": 6246,
+  "total_gz": 3269,
   "sent": [
     "fd_write"
   ],

diff --git a/test/codesize/test_codesize_hello_O3.json b/test/codesize/test_codesize_hello_O3.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 4267,
-  "a.out.js.gz": 2092,
+  "a.out.js": 4261,
+  "a.out.js.gz": 2091,
   "a.out.nodebug.wasm": 1681,
   "a.out.nodebug.wasm.gz": 960,
-  "total": 5948,
-  "total_gz": 3052,
+  "total": 5942,
+  "total_gz": 3051,
   "sent": [
     "a (fd_write)"
   ],

diff --git a/test/codesize/test_codesize_hello_Os.json b/test/codesize/test_codesize_hello_Os.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 4267,
-  "a.out.js.gz": 2092,
+  "a.out.js": 4261,
+  "a.out.js.gz": 2091,
   "a.out.nodebug.wasm": 1671,
   "a.out.nodebug.wasm.gz": 964,
-  "total": 5938,
-  "total_gz": 3056,
+  "total": 5932,
+  "total_gz": 3055,
   "sent": [
     "a (fd_write)"
   ],

diff --git a/test/codesize/test_codesize_hello_dylink.json b/test/codesize/test_codesize_hello_dylink.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 26937,
-  "a.out.js.gz": 11474,
+  "a.out.js": 26931,
+  "a.out.js.gz": 11473,
   "a.out.nodebug.wasm": 18567,
   "a.out.nodebug.wasm.gz": 9199,
-  "total": 45504,
-  "total_gz": 20673,
+  "total": 45498,
+  "total_gz": 20672,
   "sent": [
     "__heap_base",
     "__indirect_function_table",

diff --git a/test/codesize/test_codesize_hello_dylink_all.json b/test/codesize/test_codesize_hello_dylink_all.json
@@ -1,7 +1,7 @@
 {
-  "a.out.js": 245848,
-  "a.out.nodebug.wasm": 597755,
-  "total": 843603,
+  "a.out.js": 245842,
+  "a.out.nodebug.wasm": 597763,
+  "total": 843605,
   "sent": [
     "IMG_Init",
     "IMG_Load",

diff --git a/test/codesize/test_codesize_hello_single_file.json b/test/codesize/test_codesize_hello_single_file.json
@@ -1,6 +1,6 @@
 {
-  "a.out.js": 6503,
-  "a.out.js.gz": 3580,
+  "a.out.js": 6497,
+  "a.out.js.gz": 3579,
   "sent": [
     "a (fd_write)"
   ]

diff --git a/test/codesize/test_codesize_hello_wasmfs.json b/test/codesize/test_codesize_hello_wasmfs.json
@@ -1,10 +1,10 @@
 {
-  "a.out.js": 4267,
-  "a.out.js.gz": 2092,
+  "a.out.js": 4261,
+  "a.out.js.gz": 2091,
   "a.out.nodebug.wasm": 1681,
   "a.out.nodebug.wasm.gz": 960,
-  "total": 5948,
-  "total_gz": 3052,
+  "total": 5942,
+  "total_gz": 3051,
   "sent": [
     "a (fd_write)"
   ],

diff --git a/test/codesize/test_minimal_runtime_code_size_audio_worklet.json b/test/codesize/test_minimal_runtime_code_size_audio_worklet.json
@@ -1,10 +1,10 @@
 {
   "a.html": 519,
   "a.html.gz": 357,
-  "a.js": 3859,
-  "a.js.gz": 2037,
+  "a.js": 3853,
+  "a.js.gz": 2035,
   "a.wasm": 1308,
   "a.wasm.gz": 876,
-  "total": 5686,
-  "total_gz": 3270
+  "total": 5680,
+  "total_gz": 3268
 }
diff --git a/test/codesize/test_small_js_flags.json b/test/codesize/test_small_js_flags.json
@@ -1,4 +1,4 @@
 {
-  "a.out.js": 2732,
+  "a.out.js": 2726,
   "a.out.js.gz": 1495
 }
diff --git a/test/codesize/test_unoptimized_code_size.json b/test/codesize/test_unoptimized_code_size.json
@@ -1,16 +1,16 @@
 {
-  "hello_world.js": 55411,
-  "hello_world.js.gz": 17487,
+  "hello_world.js": 55400,
+  "hello_world.js.gz": 17483,
   "hello_world.wasm": 15127,
   "hello_world.wasm.gz": 7450,
-  "no_asserts.js": 26570,
-  "no_asserts.js.gz": 8870,
+  "no_asserts.js": 26559,
+  "no_asserts.js.gz": 8867,
   "no_asserts.wasm": 12227,
   "no_asserts.wasm.gz": 6010,
-  "strict.js": 53449,
-  "strict.js.gz": 16824,
+  "strict.js": 53438,
+  "strict.js.gz": 16822,
   "strict.wasm": 15127,
   "strict.wasm.gz": 7447,
-  "total": 177911,
-  "total_gz": 64088
+  "total": 177878,
+  "total_gz": 64079
 }