BridgeJS: Index known JS types for type lookup

Author: kateinoigakukun

Plugins/BridgeJS/Sources/BridgeJSCore/SwiftToSkeleton.swift

@@ -25,6 +25,11 @@ public final class SwiftToSkeleton {
         self.moduleName = moduleName
         self.exposeToGlobal = exposeToGlobal
         self.typeDeclResolver = TypeDeclResolver()
+
+        // Index known types provided by JavaScriptKit
+        self.typeDeclResolver.addSourceFile("""
+        @JSClass struct JSPromise {}
+        """)
     }
 
     public func addSourceFile(_ sourceFile: SourceFileSyntax, inputFilePath: String) {