swiftwasm · kateinoigakukun · Jun 20, 2025
diff --git a/Package.swift b/Package.swift
@@ -156,7 +156,7 @@ let package = Package(
         ),
         .testTarget(
             name: "BridgeJSRuntimeTests",
-            dependencies: ["JavaScriptKit"],
+            dependencies: ["JavaScriptKit", "JavaScriptEventLoop"],
             exclude: [
                 "bridge-js.config.json",
                 "bridge-js.d.ts",

diff --git a/Plugins/BridgeJS/Sources/BridgeJSCore/ExportSwift.swift b/Plugins/BridgeJS/Sources/BridgeJSCore/ExportSwift.swift
@@ -400,7 +400,9 @@ class ExportSwift {
             var callExpr: ExprSyntax =
                 "\(raw: callee)(\(raw: abiParameterForwardings.map { $0.description }.joined(separator: ", ")))"
             if effects.isAsync {
-                callExpr = ExprSyntax(AwaitExprSyntax(awaitKeyword: .keyword(.await), expression: callExpr))
+                callExpr = ExprSyntax(
+                    AwaitExprSyntax(awaitKeyword: .keyword(.await).with(\.trailingTrivia, .space), expression: callExpr)
+                )
             }
             if effects.isThrows {
                 callExpr = ExprSyntax(
@@ -410,6 +412,12 @@ class ExportSwift {
                     )
                 )
             }
+
+
+            if effects.isAsync, returnType != .void {
+                return CodeBlockItemSyntax(item: .init(StmtSyntax("return \(raw: callExpr).jsValue")))
+            }
+
             let retMutability = returnType == .string ? "var" : "let"
             if returnType == .void {
                 return CodeBlockItemSyntax(item: .init(ExpressionStmtSyntax(expression: callExpr)))
@@ -433,7 +441,40 @@ class ExportSwift {
         }
 
         func lowerReturnValue(returnType: BridgeType) {
-            abiReturnType = returnType.abiReturnType
+            if effects.isAsync {
+                // Async functions always return a Promise, which is a JSObject
+                _lowerReturnValue(returnType: .jsObject(nil))
+            } else {
+                _lowerReturnValue(returnType: returnType)
+            }
+        }
+
+        private func _lowerReturnValue(returnType: BridgeType) {
+            switch returnType {
+            case .void:
+                abiReturnType = nil
+            case .bool:
+                abiReturnType = .i32
+            case .int:
+                abiReturnType = .i32
+            case .float:
+                abiReturnType = .f32
+            case .double:
+                abiReturnType = .f64
+            case .string:
+                abiReturnType = nil
+            case .jsObject:
+                abiReturnType = .i32
+            case .swiftHeapObject:
+                // UnsafeMutableRawPointer is returned as an i32 pointer
+                abiReturnType = .pointer
+            }
+
+            if effects.isAsync {
+                // The return value of async function (T of `(...) async -> T`) is
+                // handled by the JSPromise.async, so we don't need to do anything here.
+                return
+            }
 
             switch returnType {
             case .void: break
@@ -474,7 +515,14 @@ class ExportSwift {
 
         func render(abiName: String) -> DeclSyntax {
             let body: CodeBlockItemListSyntax
-            if effects.isThrows {
+            if effects.isAsync {
+                body = """
+                    let ret = JSPromise.async {
+                        \(CodeBlockItemListSyntax(self.body))
+                    }.jsObject
+                    return _swift_js_retain(Int32(bitPattern: ret.id))
+                """
+            } else if effects.isThrows {
                 body = """
                     do {
                         \(CodeBlockItemListSyntax(self.body))

diff --git a/Plugins/BridgeJS/Sources/BridgeJSLink/BridgeJSLink.swift b/Plugins/BridgeJS/Sources/BridgeJSLink/BridgeJSLink.swift
@@ -126,10 +126,13 @@ struct BridgeJSLink {
                 let tmpRetBytes;
                 let tmpRetException;
                 return {
-                    /** @param {WebAssembly.Imports} importObject */
-                    addImports: (importObject) => {
+                    /**
+                     * @param {WebAssembly.Imports} importObject
+                     */
+                    addImports: (importObject, importsContext) => {
                         const bjs = {};
                         importObject["bjs"] = bjs;
+                        const imports = options.getImports(importsContext);
                         bjs["swift_js_return_string"] = function(ptr, len) {
                             const bytes = new Uint8Array(memory.buffer, ptr, len)\(sharedMemory ? ".slice()" : "");
                             tmpRetString = textDecoder.decode(bytes);
@@ -239,6 +242,14 @@ struct BridgeJSLink {
         }
 
         func call(abiName: String, returnType: BridgeType) -> String? {
+            if effects.isAsync {
+                return _call(abiName: abiName, returnType: .jsObject(nil))
+            } else {
+                return _call(abiName: abiName, returnType: returnType)
+            }
+        }
+
+        private func _call(abiName: String, returnType: BridgeType) -> String? {
             let call = "instance.exports.\(abiName)(\(parameterForwardings.joined(separator: ", ")))"
             var returnExpr: String?
 
@@ -312,8 +323,14 @@ struct BridgeJSLink {
         }
     }
 
-    private func renderTSSignature(parameters: [Parameter], returnType: BridgeType) -> String {
-        return "(\(parameters.map { "\($0.name): \($0.type.tsType)" }.joined(separator: ", "))): \(returnType.tsType)"
+    private func renderTSSignature(parameters: [Parameter], returnType: BridgeType, effects: Effects) -> String {
+        let returnTypeWithEffect: String
+        if effects.isAsync {
+            returnTypeWithEffect = "Promise<\(returnType.tsType)>"
+        } else {
+            returnTypeWithEffect = returnType.tsType
+        }
+        return "(\(parameters.map { "\($0.name): \($0.type.tsType)" }.joined(separator: ", "))): \(returnTypeWithEffect)"
     }
 
     func renderExportedFunction(function: ExportedFunction) -> (js: [String], dts: [String]) {
@@ -331,7 +348,7 @@ struct BridgeJSLink {
         )
         var dtsLines: [String] = []
         dtsLines.append(
-            "\(function.name)\(renderTSSignature(parameters: function.parameters, returnType: function.returnType));"
+            "\(function.name)\(renderTSSignature(parameters: function.parameters, returnType: function.returnType, effects: function.effects));"
         )
 
         return (funcLines, dtsLines)
@@ -362,7 +379,7 @@ struct BridgeJSLink {
             jsLines.append(contentsOf: funcLines.map { $0.indent(count: 4) })
 
             dtsExportEntryLines.append(
-                "new\(renderTSSignature(parameters: constructor.parameters, returnType: .swiftHeapObject(klass.name)));"
+                "new\(renderTSSignature(parameters: constructor.parameters, returnType: .swiftHeapObject(klass.name), effects: constructor.effects));"
                     .indent(count: 4)
             )
         }
@@ -384,7 +401,7 @@ struct BridgeJSLink {
                 ).map { $0.indent(count: 4) }
             )
             dtsTypeLines.append(
-                "\(method.name)\(renderTSSignature(parameters: method.parameters, returnType: method.returnType));"
+                "\(method.name)\(renderTSSignature(parameters: method.parameters, returnType: method.returnType, effects: method.effects));"
                     .indent(count: 4)
             )
         }
@@ -446,7 +463,7 @@ struct BridgeJSLink {
         }
 
         func call(name: String, returnType: BridgeType) {
-            let call = "options.imports.\(name)(\(parameterForwardings.joined(separator: ", ")))"
+            let call = "imports.\(name)(\(parameterForwardings.joined(separator: ", ")))"
             if returnType == .void {
                 bodyLines.append("\(call);")
             } else {
@@ -455,7 +472,7 @@ struct BridgeJSLink {
         }
 
         func callConstructor(name: String) {
-            let call = "new options.imports.\(name)(\(parameterForwardings.joined(separator: ", ")))"
+            let call = "new imports.\(name)(\(parameterForwardings.joined(separator: ", ")))"
             bodyLines.append("let ret = \(call);")
         }
 
@@ -533,9 +550,10 @@ struct BridgeJSLink {
             returnExpr: returnExpr,
             returnType: function.returnType
         )
+        let effects = Effects(isAsync: false, isThrows: false)
         importObjectBuilder.appendDts(
             [
-                "\(function.name)\(renderTSSignature(parameters: function.parameters, returnType: function.returnType));"
+                "\(function.name)\(renderTSSignature(parameters: function.parameters, returnType: function.returnType, effects: effects));"
             ]
         )
         importObjectBuilder.assignToImportObject(name: function.abiName(context: nil), function: funcLines)
@@ -610,7 +628,8 @@ struct BridgeJSLink {
         importObjectBuilder.assignToImportObject(name: abiName, function: funcLines)
         importObjectBuilder.appendDts([
             "\(type.name): {",
-            "new\(renderTSSignature(parameters: constructor.parameters, returnType: returnType));".indent(count: 4),
+            "new\(renderTSSignature(parameters: constructor.parameters, returnType: returnType, effects: Effects(isAsync: false, isThrows: false)));"
+                .indent(count: 4),
             "}",
         ])
     }

diff --git a/Plugins/BridgeJS/Sources/TS2Skeleton/JavaScript/src/index.d.ts b/Plugins/BridgeJS/Sources/TS2Skeleton/JavaScript/src/index.d.ts
@@ -12,10 +12,15 @@ export type Parameter = {
     type: BridgeType;
 }
 
+export type Effects = {
+    isAsync: boolean;
+}
+
 export type ImportFunctionSkeleton = {
     name: string;
     parameters: Parameter[];
     returnType: BridgeType;
+    effects: Effects;
     documentation: string | undefined;
 }
 

diff --git a/Plugins/BridgeJS/Sources/TS2Skeleton/JavaScript/src/processor.js b/Plugins/BridgeJS/Sources/TS2Skeleton/JavaScript/src/processor.js
@@ -162,6 +162,7 @@ export class TypeProcessor {
             parameters,
             returnType: bridgeReturnType,
             documentation,
+            effects: { isAsync: false },
         };
     }
 
@@ -341,6 +342,10 @@ export class TypeProcessor {
      * @private
      */
     visitType(type, node) {
+        // Treat A<B> and A<C> as the same type
+        if (isTypeReference(type)) {
+            type = type.target;
+        }
         const maybeProcessed = this.processedTypes.get(type);
         if (maybeProcessed) {
             return maybeProcessed;
@@ -364,8 +369,13 @@ export class TypeProcessor {
                 "object": { "jsObject": {} },
                 "symbol": { "jsObject": {} },
                 "never": { "void": {} },
+                "Promise": {
+                    "jsObject": {
+                        "_0": "JSPromise"
+                    }
+                },
             };
-            const typeString = this.checker.typeToString(type);
+            const typeString = type.getSymbol()?.name ?? this.checker.typeToString(type);
             if (typeMap[typeString]) {
                 return typeMap[typeString];
             }
@@ -377,7 +387,7 @@ export class TypeProcessor {
             if (this.checker.isTypeAssignableTo(type, this.checker.getStringType())) {
                 return { "string": {} };
             }
-            if (type.getFlags() & ts.TypeFlags.TypeParameter) {
+            if (type.isTypeParameter()) {
                 return { "jsObject": {} };
             }
 
@@ -412,3 +422,24 @@ export class TypeProcessor {
         return undefined;
     }
 }
+
+/**
+ * @param {ts.Type} type
+ * @returns {type is ts.ObjectType}
+ */
+function isObjectType(type) {
+    // @ts-ignore
+    return typeof type.objectFlags === "number";
+}
+
+/**
+ *
+ * @param {ts.Type} type
+ * @returns {type is ts.TypeReference}
+ */
+function isTypeReference(type) {
+    return (
+        isObjectType(type) &&
+        (type.objectFlags & ts.ObjectFlags.Reference) !== 0
+    );
+}
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/Inputs/Async.d.ts b/Plugins/BridgeJS/Tests/BridgeJSToolTests/Inputs/Async.d.ts
@@ -0,0 +1,7 @@
+export function asyncReturnVoid(): Promise<void>;
+export function asyncRoundTripInt(v: number): Promise<number>;
+export function asyncRoundTripString(v: string): Promise<string>;
+export function asyncRoundTripBool(v: boolean): Promise<boolean>;
+export function asyncRoundTripFloat(v: number): Promise<number>;
+export function asyncRoundTripDouble(v: number): Promise<number>;
+export function asyncRoundTripJSObject(v: any): Promise<any>;
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/Inputs/Async.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/Inputs/Async.swift
@@ -0,0 +1,19 @@
+@JS func asyncReturnVoid() async {}
+@JS func asyncRoundTripInt(_ v: Int) async -> Int {
+    return v
+}
+@JS func asyncRoundTripString(_ v: String) async -> String {
+    return v
+}
+@JS func asyncRoundTripBool(_ v: Bool) async -> Bool {
+    return v
+}
+@JS func asyncRoundTripFloat(_ v: Float) async -> Float {
+    return v
+}
+@JS func asyncRoundTripDouble(_ v: Double) async -> Double {
+    return v
+}
+@JS func asyncRoundTripJSObject(_ v: JSObject) async -> JSObject {
+    return v
+}
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Async.Export.d.ts b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Async.Export.d.ts
@@ -0,0 +1,24 @@
+// NOTICE: This is auto-generated code by BridgeJS from JavaScriptKit,
+// DO NOT EDIT.
+//
+// To update this file, just rebuild your project or run
+// `swift package bridge-js`.
+
+export type Exports = {
+    asyncReturnVoid(): Promise<void>;
+    asyncRoundTripInt(v: number): Promise<number>;
+    asyncRoundTripString(v: string): Promise<string>;
+    asyncRoundTripBool(v: boolean): Promise<boolean>;
+    asyncRoundTripFloat(v: number): Promise<number>;
+    asyncRoundTripDouble(v: number): Promise<number>;
+    asyncRoundTripJSObject(v: any): Promise<any>;
+}
+export type Imports = {
+}
+export function createInstantiator(options: {
+    imports: Imports;
+}, swift: any): Promise<{
+    addImports: (importObject: WebAssembly.Imports) => void;
+    setInstance: (instance: WebAssembly.Instance) => void;
+    createExports: (instance: WebAssembly.Instance) => Exports;
+}>;