[JS IR] export external declarations

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrModuleToJsTransformerTmp.kt

@@ -47,7 +47,7 @@ class IrModuleToJsTransformerTmp(
 
         val exportData = modules.associate { module ->
             module to module.files.associate { file ->
-                file to exportModelGenerator.generateExport(file)
+                file to exportModelGenerator.generateExportWithExternals(file)
             }
         }
 
@@ -72,7 +72,7 @@ class IrModuleToJsTransformerTmp(
         val exportModelGenerator = ExportModelGenerator(backendContext, generateNamespacesForPackages = true)
 
         val exportData = files.associate { file ->
-            file to exportModelGenerator.generateExport(file)
+            file to exportModelGenerator.generateExportWithExternals(file)
         }
 
         files.forEach { StaticMembersLowering(backendContext).lower(it) }
@@ -92,6 +92,12 @@ class IrModuleToJsTransformerTmp(
         return result
     }
 
+    private fun ExportModelGenerator.generateExportWithExternals(irFile: IrFile): List<ExportedDeclaration> {
+        val exports = generateExport(irFile)
+        val additionalExports = backendContext.externalPackageFragment[irFile.symbol]?.let { generateExport(it) } ?: emptyList()
+        return additionalExports + exports
+    }
+
     private fun generateProgramFragments(
         modules: Iterable<IrModuleFragment>,
         exportData: Map<IrModuleFragment, Map<IrFile, List<ExportedDeclaration>>>,

js/js.translator/testData/typescript-export/selectiveExport/selectiveExport.d.ts

@@ -6,10 +6,6 @@ declare namespace JS_TESTS {
         interface ExportedInternalInterface {
         }
     }
-    namespace foo {
-        interface FileLevelExportedExternalInterface {
-        }
-    }
     namespace foo {
         const exportedVal: number;
         function exportedFun(): number;
@@ -18,6 +14,10 @@ declare namespace JS_TESTS {
             readonly value: number;
         }
     }
+    namespace foo {
+        interface FileLevelExportedExternalInterface {
+        }
+    }
     namespace foo {
         const fileLevelExportedVal: number;
         function fileLevelExportedFun(): number;