Slightly less hacky version to avoid dynamic import

See #245

Author: jrouwe

CMakeLists.txt

@@ -86,9 +86,9 @@ else()
 	set(REMOVE_THREAD_LOCAL sed -i.bak -e "s:thread_local::g" glue.cpp)
 endif()
 
-# Replace '("ReplaceWithImport"' with 'import(' in the generated JS code to workaround a bug in emscripten
+# Replace 'replace_by_import' by 'import' in the generated JS code to workaround a bug in emscripten
 # See: https://github.com/jrouwe/JoltPhysics.js/issues/245
-set(REPLACE_IMPORT sed -i -e "s:(\"ReplaceWithImport\"+:import(:g")
+set(REPLACE_IMPORT sed -i -e "s:replace_by_import:import:g")
 
 # Enable SIMD flags
 if (ENABLE_SIMD)
@@ -136,6 +136,9 @@ set(EMCC_ARGS
   --extern-pre-js ${JOLT_FRONT_MATTER_FILE}
   --post-js glue.js
   --closure=1
+  --closure-args="--dynamic_import_alias=replace_by_import"
+  --closure-args="--externs"
+  --closure-args="${CMAKE_CURRENT_SOURCE_DIR}/extern-import.js"
   ${MULTI_THREADED_FLAG}
   --post-js ${CMAKE_CURRENT_SOURCE_DIR}/helpers.js
   ${MEMORY_GROWTH_FLAG}

extern-import.js

@@ -0,0 +1,3 @@
+// A hack to not have to use 'import' in multi-threaded.js
+// See: https://github.com/jrouwe/JoltPhysics.js/issues/245
+var replace_by_import = (a) => { };

multi-threaded.js

@@ -4,9 +4,8 @@ if (ENVIRONMENT_IS_PTHREAD) {
 	invokeEntryPoint = (ptr, arg) => {
 		if (arg.script) {
 			// Workaround for bug: https://github.com/jrouwe/JoltPhysics.js/issues/245
-			// '("ReplaceWithImport"+arg.script)' should be 'import(arg.script)'
-			// This gets replaced by sed during the build process.
-			("ReplaceWithImport"+arg.script).then(module => {
+			// `replace_by_import` gets replaced by `import`
+			replace_by_import(arg.script).then(module => {
 				module.default(Module, arg.params).then(() => _invokeEntryPoint(ptr, arg.value));
 			})
 		} else {