diff --git a/src/parseTools.mjs b/src/parseTools.mjs
index ca474affa3978..fa6da8556e314 100644
--- a/src/parseTools.mjs
+++ b/src/parseTools.mjs
@@ -785,24 +785,16 @@ export function modifyJSFunction(text, func) {
 }
 
 export function runIfMainThread(text) {
-  if (WASM_WORKERS && PTHREADS) {
-    return `if (!ENVIRONMENT_IS_WASM_WORKER && !ENVIRONMENT_IS_PTHREAD) { ${text} }`;
-  } else if (WASM_WORKERS) {
-    return `if (!ENVIRONMENT_IS_WASM_WORKER) { ${text} }`;
-  } else if (PTHREADS) {
-    return `if (!ENVIRONMENT_IS_PTHREAD) { ${text} }`;
+  if (WASM_WORKERS || PTHREADS) {
+    return `if (${ENVIRONMENT_IS_MAIN_THREAD()}) { ${text} }`;
   } else {
     return text;
   }
 }
 
 function runIfWorkerThread(text) {
-  if (WASM_WORKERS && PTHREADS) {
-    return `if (ENVIRONMENT_IS_WASM_WORKER || ENVIRONMENT_IS_PTHREAD) { ${text} }`;
-  } else if (WASM_WORKERS) {
-    return `if (ENVIRONMENT_IS_WASM_WORKER) { ${text} }`;
-  } else if (PTHREADS) {
-    return `if (ENVIRONMENT_IS_PTHREAD) { ${text} }`;
+  if (WASM_WORKERS || PTHREADS) {
+    return `if (${ENVIRONMENT_IS_WORKER_THREAD()}) { ${text} }`;
   } else {
     return '';
   }
@@ -1094,12 +1086,15 @@ function implicitSelf() {
 }
 
 function ENVIRONMENT_IS_MAIN_THREAD() {
+  return `(!${ENVIRONMENT_IS_WORKER_THREAD()})`;
+}
+
+function ENVIRONMENT_IS_WORKER_THREAD() {
+  assert(PTHREADS || WASM_WORKERS);
   var envs = [];
   if (PTHREADS) envs.push('ENVIRONMENT_IS_PTHREAD');
   if (WASM_WORKERS) envs.push('ENVIRONMENT_IS_WASM_WORKER');
-  if (AUDIO_WORKLET) envs.push('ENVIRONMENT_IS_AUDIO_WORKLET');
-  if (envs.length == 0) return 'true';
-  return '(!(' + envs.join('||') + '))';
+  return '(' + envs.join('||') + ')';
 }
 
 addToCompileTimeContext({
@@ -1120,6 +1115,7 @@ addToCompileTimeContext({
   TARGET_NOT_SUPPORTED,
   WASM_PAGE_SIZE,
   ENVIRONMENT_IS_MAIN_THREAD,
+  ENVIRONMENT_IS_WORKER_THREAD,
   addAtExit,
   addAtInit,
   addReadyPromiseAssertions,
diff --git a/src/postamble.js b/src/postamble.js
index 075ed1048e48d..c4c25cfb4a8d8 100644
--- a/src/postamble.js
+++ b/src/postamble.js
@@ -161,25 +161,12 @@ function run() {
     return;
   }
 
-#if WASM_WORKERS
-  if (ENVIRONMENT_IS_WASM_WORKER) {
+#if PTHREADS || WASM_WORKERS
+  if ({{{ ENVIRONMENT_IS_WORKER_THREAD() }}}) {
 #if MODULARIZE
     readyPromiseResolve(Module);
-#endif // MODULARIZE
-    return initRuntime();
-  }
 #endif
-
-#if PTHREADS
-  if (ENVIRONMENT_IS_PTHREAD) {
-#if MODULARIZE
-    // The promise resolve function typically gets called as part of the execution
-    // of `doRun` below. The workers/pthreads don't execute `doRun` so the
-    // creation promise can be resolved, marking the pthread-Module as initialized.
-    readyPromiseResolve(Module);
-#endif // MODULARIZE
     initRuntime();
-    startWorker(Module);
     return;
   }
 #endif
diff --git a/src/preamble.js b/src/preamble.js
index 23ee003bb5592..1ca3da0389a93 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -219,7 +219,7 @@ function initRuntime() {
 #endif
 
 #if PTHREADS
-  if (ENVIRONMENT_IS_PTHREAD) return;
+  if (ENVIRONMENT_IS_PTHREAD) return startWorker(Module);
 #endif
 
 #if STACK_OVERFLOW_CHECK
diff --git a/test/code_size/hello_wasm_worker_wasm.js b/test/code_size/hello_wasm_worker_wasm.js
index 4e7446cc3dfa6..b1805d122420e 100644
--- a/test/code_size/hello_wasm_worker_wasm.js
+++ b/test/code_size/hello_wasm_worker_wasm.js
@@ -46,5 +46,5 @@ WebAssembly.instantiate(b.wasm, {
     h = a.h;
     c ? (a = b, q(a.sb, a.sz), removeEventListener("message", l), g = g.forEach(k), 
     addEventListener("message", k)) : a.f();
-    c || p();
+    p();
 }));
\ No newline at end of file
diff --git a/test/code_size/hello_wasm_worker_wasm.json b/test/code_size/hello_wasm_worker_wasm.json
index 870b7172314c4..3d369c175bb03 100644
--- a/test/code_size/hello_wasm_worker_wasm.json
+++ b/test/code_size/hello_wasm_worker_wasm.json
@@ -1,12 +1,12 @@
 {
   "a.html": 618,
   "a.html.gz": 384,
-  "a.js": 665,
-  "a.js.gz": 455,
+  "a.js": 662,
+  "a.js.gz": 452,
   "a.ww.js": 115,
   "a.ww.js.gz": 127,
   "a.wasm": 1881,
   "a.wasm.gz": 1065,
-  "total": 3279,
-  "total_gz": 2031
+  "total": 3276,
+  "total_gz": 2028
 }
diff --git a/test/other/codesize/test_codesize_minimal_pthreads.gzsize b/test/other/codesize/test_codesize_minimal_pthreads.gzsize
index 0f12704884a5d..e47cad5f248ac 100644
--- a/test/other/codesize/test_codesize_minimal_pthreads.gzsize
+++ b/test/other/codesize/test_codesize_minimal_pthreads.gzsize
@@ -1 +1 @@
-4208
+4209
diff --git a/test/other/codesize/test_codesize_minimal_pthreads.jssize b/test/other/codesize/test_codesize_minimal_pthreads.jssize
index db6dfb1df8651..7db41a45918a0 100644
--- a/test/other/codesize/test_codesize_minimal_pthreads.jssize
+++ b/test/other/codesize/test_codesize_minimal_pthreads.jssize
@@ -1 +1 @@
-8703
+8716