diff --git a/Plugins/BridgeJS/README.md b/Plugins/BridgeJS/README.md
index 2fb6458a..f762c294 100644
--- a/Plugins/BridgeJS/README.md
+++ b/Plugins/BridgeJS/README.md
@@ -135,3 +135,4 @@ TBD
     declare var Foo: FooConstructor;
     ```
 - [ ] Use `externref` once it's widely available
+- [ ] Test SwiftObject roundtrip
\ No newline at end of file
diff --git a/Plugins/BridgeJS/Sources/BridgeJSLink/BridgeJSLink.swift b/Plugins/BridgeJS/Sources/BridgeJSLink/BridgeJSLink.swift
index b2bdbe84..f1605670 100644
--- a/Plugins/BridgeJS/Sources/BridgeJSLink/BridgeJSLink.swift
+++ b/Plugins/BridgeJS/Sources/BridgeJSLink/BridgeJSLink.swift
@@ -111,6 +111,7 @@ struct BridgeJSLink {
 
                 let tmpRetString;
                 let tmpRetBytes;
+                let tmpRetException;
                 return {
                     /** @param {WebAssembly.Imports} importObject */
                     addImports: (importObject) => {
@@ -134,6 +135,9 @@ struct BridgeJSLink {
                             target.set(tmpRetBytes);
                             tmpRetBytes = undefined;
                         }
+                        bjs["swift_js_throw"] = function(id) {
+                            tmpRetException = swift.memory.retainByRef(id);
+                        }
                         bjs["swift_js_retain"] = function(id) {
                             return swift.memory.retainByRef(id);
                         }
@@ -188,6 +192,11 @@ struct BridgeJSLink {
         var bodyLines: [String] = []
         var cleanupLines: [String] = []
         var parameterForwardings: [String] = []
+        let effects: Effects
+
+        init(effects: Effects) {
+            self.effects = effects
+        }
 
         func lowerParameter(param: Parameter) {
             switch param.type {
@@ -245,7 +254,24 @@ struct BridgeJSLink {
         }
 
         func callConstructor(abiName: String) -> String {
-            return "instance.exports.\(abiName)(\(parameterForwardings.joined(separator: ", ")))"
+            let call = "instance.exports.\(abiName)(\(parameterForwardings.joined(separator: ", ")))"
+            bodyLines.append("const ret = \(call);")
+            return "ret"
+        }
+
+        func checkExceptionLines() -> [String] {
+            guard effects.isThrows else {
+                return []
+            }
+            return [
+                "if (tmpRetException) {",
+                // TODO: Implement "take" operation
+                "    const error = swift.memory.getObject(tmpRetException);",
+                "    swift.memory.release(tmpRetException);",
+                "    tmpRetException = undefined;",
+                "    throw error;",
+                "}",
+            ]
         }
 
         func renderFunction(
@@ -261,6 +287,7 @@ struct BridgeJSLink {
             )
             funcLines.append(contentsOf: bodyLines.map { $0.indent(count: 4) })
             funcLines.append(contentsOf: cleanupLines.map { $0.indent(count: 4) })
+            funcLines.append(contentsOf: checkExceptionLines().map { $0.indent(count: 4) })
             if let returnExpr = returnExpr {
                 funcLines.append("return \(returnExpr);".indent(count: 4))
             }
@@ -274,7 +301,7 @@ struct BridgeJSLink {
     }
 
     func renderExportedFunction(function: ExportedFunction) -> (js: [String], dts: [String]) {
-        let thunkBuilder = ExportedThunkBuilder()
+        let thunkBuilder = ExportedThunkBuilder(effects: function.effects)
         for param in function.parameters {
             thunkBuilder.lowerParameter(param: param)
         }
@@ -304,16 +331,17 @@ struct BridgeJSLink {
         jsLines.append("class \(klass.name) extends SwiftHeapObject {")
 
         if let constructor: ExportedConstructor = klass.constructor {
-            let thunkBuilder = ExportedThunkBuilder()
+            let thunkBuilder = ExportedThunkBuilder(effects: constructor.effects)
             for param in constructor.parameters {
                 thunkBuilder.lowerParameter(param: param)
             }
-            let returnExpr = thunkBuilder.callConstructor(abiName: constructor.abiName)
             var funcLines: [String] = []
             funcLines.append("constructor(\(constructor.parameters.map { $0.name }.joined(separator: ", "))) {")
+            let returnExpr = thunkBuilder.callConstructor(abiName: constructor.abiName)
             funcLines.append(contentsOf: thunkBuilder.bodyLines.map { $0.indent(count: 4) })
-            funcLines.append("super(\(returnExpr), instance.exports.bjs_\(klass.name)_deinit);".indent(count: 4))
             funcLines.append(contentsOf: thunkBuilder.cleanupLines.map { $0.indent(count: 4) })
+            funcLines.append(contentsOf: thunkBuilder.checkExceptionLines().map { $0.indent(count: 4) })
+            funcLines.append("super(\(returnExpr), instance.exports.bjs_\(klass.name)_deinit);".indent(count: 4))
             funcLines.append("}")
             jsLines.append(contentsOf: funcLines.map { $0.indent(count: 4) })
 
@@ -324,7 +352,7 @@ struct BridgeJSLink {
         }
 
         for method in klass.methods {
-            let thunkBuilder = ExportedThunkBuilder()
+            let thunkBuilder = ExportedThunkBuilder(effects: method.effects)
             thunkBuilder.lowerSelf()
             for param in method.parameters {
                 thunkBuilder.lowerParameter(param: param)
diff --git a/Plugins/BridgeJS/Sources/BridgeJSSkeleton/BridgeJSSkeleton.swift b/Plugins/BridgeJS/Sources/BridgeJSSkeleton/BridgeJSSkeleton.swift
index 34492682..873849f9 100644
--- a/Plugins/BridgeJS/Sources/BridgeJSSkeleton/BridgeJSSkeleton.swift
+++ b/Plugins/BridgeJS/Sources/BridgeJSSkeleton/BridgeJSSkeleton.swift
@@ -16,6 +16,11 @@ struct Parameter: Codable {
     let type: BridgeType
 }
 
+struct Effects: Codable {
+    var isAsync: Bool
+    var isThrows: Bool
+}
+
 // MARK: - Exported Skeleton
 
 struct ExportedFunction: Codable {
@@ -23,6 +28,7 @@ struct ExportedFunction: Codable {
     var abiName: String
     var parameters: [Parameter]
     var returnType: BridgeType
+    var effects: Effects
 }
 
 struct ExportedClass: Codable {
@@ -34,6 +40,7 @@ struct ExportedClass: Codable {
 struct ExportedConstructor: Codable {
     var abiName: String
     var parameters: [Parameter]
+    var effects: Effects
 }
 
 struct ExportedSkeleton: Codable {
diff --git a/Plugins/BridgeJS/Sources/BridgeJSTool/ExportSwift.swift b/Plugins/BridgeJS/Sources/BridgeJSTool/ExportSwift.swift
index 25b1ed01..291c4a33 100644
--- a/Plugins/BridgeJS/Sources/BridgeJSTool/ExportSwift.swift
+++ b/Plugins/BridgeJS/Sources/BridgeJSTool/ExportSwift.swift
@@ -155,14 +155,43 @@ class ExportSwift {
                 abiName = "bjs_\(className)_\(name)"
             }
 
+            guard let effects = collectEffects(signature: node.signature) else {
+                return nil
+            }
+
             return ExportedFunction(
                 name: name,
                 abiName: abiName,
                 parameters: parameters,
-                returnType: returnType
+                returnType: returnType,
+                effects: effects
             )
         }
 
+        private func collectEffects(signature: FunctionSignatureSyntax) -> Effects? {
+            let isAsync = signature.effectSpecifiers?.asyncSpecifier != nil
+            var isThrows = false
+            if let throwsClause: ThrowsClauseSyntax = signature.effectSpecifiers?.throwsClause {
+                // Limit the thrown type to JSException for now
+                guard let thrownType = throwsClause.type else {
+                    diagnose(
+                        node: throwsClause,
+                        message: "Thrown type is not specified, only JSException is supported for now"
+                    )
+                    return nil
+                }
+                guard thrownType.trimmedDescription == "JSException" else {
+                    diagnose(
+                        node: throwsClause,
+                        message: "Only JSException is supported for thrown type, got \(thrownType.trimmedDescription)"
+                    )
+                    return nil
+                }
+                isThrows = true
+            }
+            return Effects(isAsync: isAsync, isThrows: isThrows)
+        }
+
         override func visit(_ node: InitializerDeclSyntax) -> SyntaxVisitorContinueKind {
             guard node.attributes.hasJSAttribute() else { return .skipChildren }
             guard case .classBody(let name) = state else {
@@ -180,9 +209,14 @@ class ExportSwift {
                 parameters.append(Parameter(label: label, name: name, type: type))
             }
 
+            guard let effects = collectEffects(signature: node.signature) else {
+                return .skipChildren
+            }
+
             let constructor = ExportedConstructor(
                 abiName: "bjs_\(name)_init",
-                parameters: parameters
+                parameters: parameters,
+                effects: effects
             )
             exportedClasses[name]?.constructor = constructor
             return .skipChildren
@@ -245,6 +279,8 @@ class ExportSwift {
 
         @_extern(wasm, module: "bjs", name: "swift_js_retain")
         private func _swift_js_retain(_ ptr: Int32) -> Int32
+        @_extern(wasm, module: "bjs", name: "swift_js_throw")
+        private func _swift_js_throw(_ id: Int32)
         """
 
     func renderSwiftGlue() -> String? {
@@ -268,6 +304,11 @@ class ExportSwift {
         var abiParameterForwardings: [LabeledExprSyntax] = []
         var abiParameterSignatures: [(name: String, type: WasmCoreType)] = []
         var abiReturnType: WasmCoreType?
+        let effects: Effects
+
+        init(effects: Effects) {
+            self.effects = effects
+        }
 
         func liftParameter(param: Parameter) {
             switch param.type {
@@ -350,35 +391,40 @@ class ExportSwift {
             }
         }
 
-        func call(name: String, returnType: BridgeType) {
+        private func renderCallStatement(callee: ExprSyntax, returnType: BridgeType) -> StmtSyntax {
+            var callExpr: ExprSyntax =
+                "\(raw: callee)(\(raw: abiParameterForwardings.map { $0.description }.joined(separator: ", ")))"
+            if effects.isAsync {
+                callExpr = ExprSyntax(AwaitExprSyntax(awaitKeyword: .keyword(.await), expression: callExpr))
+            }
+            if effects.isThrows {
+                callExpr = ExprSyntax(
+                    TryExprSyntax(
+                        tryKeyword: .keyword(.try).with(\.trailingTrivia, .space),
+                        expression: callExpr
+                    )
+                )
+            }
             let retMutability = returnType == .string ? "var" : "let"
-            let callExpr: ExprSyntax =
-                "\(raw: name)(\(raw: abiParameterForwardings.map { $0.description }.joined(separator: ", ")))"
             if returnType == .void {
-                body.append("\(raw: callExpr)")
+                return StmtSyntax("\(raw: callExpr)")
             } else {
-                body.append(
-                    """
-                    \(raw: retMutability) ret = \(raw: callExpr)
-                    """
-                )
+                return StmtSyntax("\(raw: retMutability) ret = \(raw: callExpr)")
             }
         }
 
+        func call(name: String, returnType: BridgeType) {
+            let stmt = renderCallStatement(callee: "\(raw: name)", returnType: returnType)
+            body.append(CodeBlockItemSyntax(item: .stmt(stmt)))
+        }
+
         func callMethod(klassName: String, methodName: String, returnType: BridgeType) {
             let _selfParam = self.abiParameterForwardings.removeFirst()
-            let retMutability = returnType == .string ? "var" : "let"
-            let callExpr: ExprSyntax =
-                "\(raw: _selfParam).\(raw: methodName)(\(raw: abiParameterForwardings.map { $0.description }.joined(separator: ", ")))"
-            if returnType == .void {
-                body.append("\(raw: callExpr)")
-            } else {
-                body.append(
-                    """
-                    \(raw: retMutability) ret = \(raw: callExpr)
-                    """
-                )
-            }
+            let stmt = renderCallStatement(
+                callee: "\(raw: _selfParam).\(raw: methodName)",
+                returnType: returnType
+            )
+            body.append(CodeBlockItemSyntax(item: .stmt(stmt)))
         }
 
         func lowerReturnValue(returnType: BridgeType) {
@@ -440,19 +486,54 @@ class ExportSwift {
         }
 
         func render(abiName: String) -> DeclSyntax {
+            let body: CodeBlockItemListSyntax
+            if effects.isThrows {
+                body = """
+                    do {
+                        \(CodeBlockItemListSyntax(self.body))
+                    } catch let error {
+                        if let error = error.thrownValue.object {
+                            withExtendedLifetime(error) {
+                                _swift_js_throw(Int32(bitPattern: $0.id))
+                            }
+                        } else {
+                            let jsError = JSError(message: String(describing: error))
+                            withExtendedLifetime(jsError.jsObject) {
+                                _swift_js_throw(Int32(bitPattern: $0.id))
+                            }
+                        }
+                        \(raw: returnPlaceholderStmt())
+                    }
+                    """
+            } else {
+                body = CodeBlockItemListSyntax(self.body)
+            }
             return """
                 @_expose(wasm, "\(raw: abiName)")
                 @_cdecl("\(raw: abiName)")
                 public func _\(raw: abiName)(\(raw: parameterSignature())) -> \(raw: returnSignature()) {
-                \(CodeBlockItemListSyntax(body))
+                \(body)
                 }
                 """
         }
 
+        private func returnPlaceholderStmt() -> String {
+            switch abiReturnType {
+            case .i32: return "return 0"
+            case .i64: return "return 0"
+            case .f32: return "return 0.0"
+            case .f64: return "return 0.0"
+            case .pointer: return "return UnsafeMutableRawPointer(bitPattern: -1)"
+            case .none: return "return"
+            }
+        }
+
         func parameterSignature() -> String {
-            abiParameterSignatures.map { "\($0.name): \($0.type.swiftType)" }.joined(
-                separator: ", "
-            )
+            var nameAndType: [(name: String, abiType: String)] = []
+            for (name, type) in abiParameterSignatures {
+                nameAndType.append((name, type.swiftType))
+            }
+            return nameAndType.map { "\($0.name): \($0.abiType)" }.joined(separator: ", ")
         }
 
         func returnSignature() -> String {
@@ -461,7 +542,7 @@ class ExportSwift {
     }
 
     func renderSingleExportedFunction(function: ExportedFunction) -> DeclSyntax {
-        let builder = ExportedThunkBuilder()
+        let builder = ExportedThunkBuilder(effects: function.effects)
         for param in function.parameters {
             builder.liftParameter(param: param)
         }
@@ -520,7 +601,7 @@ class ExportSwift {
     func renderSingleExportedClass(klass: ExportedClass) -> [DeclSyntax] {
         var decls: [DeclSyntax] = []
         if let constructor = klass.constructor {
-            let builder = ExportedThunkBuilder()
+            let builder = ExportedThunkBuilder(effects: constructor.effects)
             for param in constructor.parameters {
                 builder.liftParameter(param: param)
             }
@@ -529,7 +610,7 @@ class ExportSwift {
             decls.append(builder.render(abiName: constructor.abiName))
         }
         for method in klass.methods {
-            let builder = ExportedThunkBuilder()
+            let builder = ExportedThunkBuilder(effects: method.effects)
             builder.liftParameter(
                 param: Parameter(label: nil, name: "_self", type: .swiftHeapObject(klass.name))
             )
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/Inputs/Throws.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/Inputs/Throws.swift
new file mode 100644
index 00000000..ce8c30fe
--- /dev/null
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/Inputs/Throws.swift
@@ -0,0 +1,3 @@
+@JS func throwsSomething() throws(JSException) {
+    throw JSException(JSError(message: "TestError").jsValue)
+}
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/ArrayParameter.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/ArrayParameter.Import.js
index 73ef604f..1e9fa9d0 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/ArrayParameter.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/ArrayParameter.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Interface.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Interface.Import.js
index 940c565f..328ff199 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Interface.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Interface.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveParameters.Export.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveParameters.Export.js
index a5b206c5..c86f3fea 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveParameters.Export.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveParameters.Export.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveParameters.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveParameters.Import.js
index 7217750a..584e1308 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveParameters.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveParameters.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveReturn.Export.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveReturn.Export.js
index 3480cc97..d8b29c90 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveReturn.Export.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveReturn.Export.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveReturn.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveReturn.Import.js
index 5aba76f1..42f805e4 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveReturn.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/PrimitiveReturn.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringParameter.Export.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringParameter.Export.js
index c9397bbd..e6dab48d 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringParameter.Export.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringParameter.Export.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringParameter.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringParameter.Import.js
index 5b9808f6..844f6f35 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringParameter.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringParameter.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringReturn.Export.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringReturn.Export.js
index caa68521..76710fa7 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringReturn.Export.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringReturn.Export.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringReturn.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringReturn.Import.js
index dfc6f048..abf1ea28 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringReturn.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/StringReturn.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/SwiftClass.Export.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/SwiftClass.Export.js
index 6b30cd68..0595b35a 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/SwiftClass.Export.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/SwiftClass.Export.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
@@ -71,8 +75,9 @@ export async function createInstantiator(options, swift) {
                 constructor(name) {
                     const nameBytes = textEncoder.encode(name);
                     const nameId = swift.memory.retain(nameBytes);
-                    super(instance.exports.bjs_Greeter_init(nameId, nameBytes.length), instance.exports.bjs_Greeter_deinit);
+                    const ret = instance.exports.bjs_Greeter_init(nameId, nameBytes.length);
                     swift.memory.release(nameId);
+                    super(ret, instance.exports.bjs_Greeter_deinit);
                 }
                 greet() {
                     instance.exports.bjs_Greeter_greet(this.pointer);
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Throws.Export.d.ts b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Throws.Export.d.ts
new file mode 100644
index 00000000..9199ad1a
--- /dev/null
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Throws.Export.d.ts
@@ -0,0 +1,18 @@
+// 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 = {
+    throwsSomething(): void;
+}
+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;
+}>;
\ No newline at end of file
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Throws.Export.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Throws.Export.js
new file mode 100644
index 00000000..f15135ff
--- /dev/null
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/Throws.Export.js
@@ -0,0 +1,71 @@
+// 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 async function createInstantiator(options, swift) {
+    let instance;
+    let memory;
+    const textDecoder = new TextDecoder("utf-8");
+    const textEncoder = new TextEncoder("utf-8");
+
+    let tmpRetString;
+    let tmpRetBytes;
+    let tmpRetException;
+    return {
+        /** @param {WebAssembly.Imports} importObject */
+        addImports: (importObject) => {
+            const bjs = {};
+            importObject["bjs"] = bjs;
+            bjs["return_string"] = function(ptr, len) {
+                const bytes = new Uint8Array(memory.buffer, ptr, len);
+                tmpRetString = textDecoder.decode(bytes);
+            }
+            bjs["init_memory"] = function(sourceId, bytesPtr) {
+                const source = swift.memory.getObject(sourceId);
+                const bytes = new Uint8Array(memory.buffer, bytesPtr);
+                bytes.set(source);
+            }
+            bjs["make_jsstring"] = function(ptr, len) {
+                const bytes = new Uint8Array(memory.buffer, ptr, len);
+                return swift.memory.retain(textDecoder.decode(bytes));
+            }
+            bjs["init_memory_with_result"] = function(ptr, len) {
+                const target = new Uint8Array(memory.buffer, ptr, len);
+                target.set(tmpRetBytes);
+                tmpRetBytes = undefined;
+            }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
+            bjs["swift_js_retain"] = function(id) {
+                return swift.memory.retainByRef(id);
+            }
+            bjs["swift_js_release"] = function(id) {
+                swift.memory.release(id);
+            }
+
+        },
+        setInstance: (i) => {
+            instance = i;
+            memory = instance.exports.memory;
+        },
+        /** @param {WebAssembly.Instance} instance */
+        createExports: (instance) => {
+            const js = swift.memory.heap;
+
+            return {
+                throwsSomething: function bjs_throwsSomething() {
+                    instance.exports.bjs_throwsSomething();
+                    if (tmpRetException) {
+                        const error = swift.memory.getObject(tmpRetException);
+                        swift.memory.release(tmpRetException);
+                        tmpRetException = undefined;
+                        throw error;
+                    }
+                },
+            };
+        },
+    }
+}
\ No newline at end of file
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/TypeAlias.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/TypeAlias.Import.js
index 71133762..39306e28 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/TypeAlias.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/TypeAlias.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/TypeScriptClass.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/TypeScriptClass.Import.js
index f86e6054..1e893f6e 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/TypeScriptClass.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/TypeScriptClass.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/VoidParameterVoidReturn.Export.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/VoidParameterVoidReturn.Export.js
index 166eeed0..01daf861 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/VoidParameterVoidReturn.Export.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/VoidParameterVoidReturn.Export.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/VoidParameterVoidReturn.Import.js b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/VoidParameterVoidReturn.Import.js
index 91b344c3..0fef27b4 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/VoidParameterVoidReturn.Import.js
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/BridgeJSLinkTests/VoidParameterVoidReturn.Import.js
@@ -12,6 +12,7 @@ export async function createInstantiator(options, swift) {
 
     let tmpRetString;
     let tmpRetBytes;
+    let tmpRetException;
     return {
         /** @param {WebAssembly.Imports} importObject */
         addImports: (importObject) => {
@@ -35,6 +36,9 @@ export async function createInstantiator(options, swift) {
                 target.set(tmpRetBytes);
                 tmpRetBytes = undefined;
             }
+            bjs["swift_js_throw"] = function(id) {
+                tmpRetException = swift.memory.retainByRef(id);
+            }
             bjs["swift_js_retain"] = function(id) {
                 return swift.memory.retainByRef(id);
             }
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveParameters.json b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveParameters.json
index 4b2dafa1..23fdeab8 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveParameters.json
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveParameters.json
@@ -5,6 +5,10 @@
   "functions" : [
     {
       "abiName" : "bjs_check",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "check",
       "parameters" : [
         {
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveParameters.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveParameters.swift
index 5181eece..8606b6d6 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveParameters.swift
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveParameters.swift
@@ -13,6 +13,8 @@ private func _init_memory(_ sourceId: Int32, _ ptr: UnsafeMutablePointer<UInt8>?
 
 @_extern(wasm, module: "bjs", name: "swift_js_retain")
 private func _swift_js_retain(_ ptr: Int32) -> Int32
+@_extern(wasm, module: "bjs", name: "swift_js_throw")
+private func _swift_js_throw(_ id: Int32)
 
 @_expose(wasm, "bjs_check")
 @_cdecl("bjs_check")
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveReturn.json b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveReturn.json
index ae672cb5..f517c68a 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveReturn.json
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveReturn.json
@@ -5,6 +5,10 @@
   "functions" : [
     {
       "abiName" : "bjs_checkInt",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "checkInt",
       "parameters" : [
 
@@ -17,6 +21,10 @@
     },
     {
       "abiName" : "bjs_checkFloat",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "checkFloat",
       "parameters" : [
 
@@ -29,6 +37,10 @@
     },
     {
       "abiName" : "bjs_checkDouble",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "checkDouble",
       "parameters" : [
 
@@ -41,6 +53,10 @@
     },
     {
       "abiName" : "bjs_checkBool",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "checkBool",
       "parameters" : [
 
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveReturn.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveReturn.swift
index fb624231..314f916f 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveReturn.swift
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/PrimitiveReturn.swift
@@ -13,6 +13,8 @@ private func _init_memory(_ sourceId: Int32, _ ptr: UnsafeMutablePointer<UInt8>?
 
 @_extern(wasm, module: "bjs", name: "swift_js_retain")
 private func _swift_js_retain(_ ptr: Int32) -> Int32
+@_extern(wasm, module: "bjs", name: "swift_js_throw")
+private func _swift_js_throw(_ id: Int32)
 
 @_expose(wasm, "bjs_checkInt")
 @_cdecl("bjs_checkInt")
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringParameter.json b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringParameter.json
index 0fea9735..a86fb67e 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringParameter.json
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringParameter.json
@@ -5,6 +5,10 @@
   "functions" : [
     {
       "abiName" : "bjs_checkString",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "checkString",
       "parameters" : [
         {
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringParameter.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringParameter.swift
index d16cd81c..cbe2fb89 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringParameter.swift
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringParameter.swift
@@ -13,6 +13,8 @@ private func _init_memory(_ sourceId: Int32, _ ptr: UnsafeMutablePointer<UInt8>?
 
 @_extern(wasm, module: "bjs", name: "swift_js_retain")
 private func _swift_js_retain(_ ptr: Int32) -> Int32
+@_extern(wasm, module: "bjs", name: "swift_js_throw")
+private func _swift_js_throw(_ id: Int32)
 
 @_expose(wasm, "bjs_checkString")
 @_cdecl("bjs_checkString")
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringReturn.json b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringReturn.json
index c773d0d2..b5536572 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringReturn.json
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringReturn.json
@@ -5,6 +5,10 @@
   "functions" : [
     {
       "abiName" : "bjs_checkString",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "checkString",
       "parameters" : [
 
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringReturn.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringReturn.swift
index 4f3a9e89..e3fc3813 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringReturn.swift
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/StringReturn.swift
@@ -13,6 +13,8 @@ private func _init_memory(_ sourceId: Int32, _ ptr: UnsafeMutablePointer<UInt8>?
 
 @_extern(wasm, module: "bjs", name: "swift_js_retain")
 private func _swift_js_retain(_ ptr: Int32) -> Int32
+@_extern(wasm, module: "bjs", name: "swift_js_throw")
+private func _swift_js_throw(_ id: Int32)
 
 @_expose(wasm, "bjs_checkString")
 @_cdecl("bjs_checkString")
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/SwiftClass.json b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/SwiftClass.json
index 2aff4c93..d37a9254 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/SwiftClass.json
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/SwiftClass.json
@@ -3,6 +3,10 @@
     {
       "constructor" : {
         "abiName" : "bjs_Greeter_init",
+        "effects" : {
+          "isAsync" : false,
+          "isThrows" : false
+        },
         "parameters" : [
           {
             "label" : "name",
@@ -18,6 +22,10 @@
       "methods" : [
         {
           "abiName" : "bjs_Greeter_greet",
+          "effects" : {
+            "isAsync" : false,
+            "isThrows" : false
+          },
           "name" : "greet",
           "parameters" : [
 
@@ -30,6 +38,10 @@
         },
         {
           "abiName" : "bjs_Greeter_changeName",
+          "effects" : {
+            "isAsync" : false,
+            "isThrows" : false
+          },
           "name" : "changeName",
           "parameters" : [
             {
@@ -55,6 +67,10 @@
   "functions" : [
     {
       "abiName" : "bjs_takeGreeter",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "takeGreeter",
       "parameters" : [
         {
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/SwiftClass.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/SwiftClass.swift
index fa0190f7..5602deba 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/SwiftClass.swift
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/SwiftClass.swift
@@ -13,6 +13,8 @@ private func _init_memory(_ sourceId: Int32, _ ptr: UnsafeMutablePointer<UInt8>?
 
 @_extern(wasm, module: "bjs", name: "swift_js_retain")
 private func _swift_js_retain(_ ptr: Int32) -> Int32
+@_extern(wasm, module: "bjs", name: "swift_js_throw")
+private func _swift_js_throw(_ id: Int32)
 
 @_expose(wasm, "bjs_takeGreeter")
 @_cdecl("bjs_takeGreeter")
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/Throws.json b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/Throws.json
new file mode 100644
index 00000000..05363283
--- /dev/null
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/Throws.json
@@ -0,0 +1,23 @@
+{
+  "classes" : [
+
+  ],
+  "functions" : [
+    {
+      "abiName" : "bjs_throwsSomething",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : true
+      },
+      "name" : "throwsSomething",
+      "parameters" : [
+
+      ],
+      "returnType" : {
+        "void" : {
+
+        }
+      }
+    }
+  ]
+}
\ No newline at end of file
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/Throws.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/Throws.swift
new file mode 100644
index 00000000..73b8f492
--- /dev/null
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/Throws.swift
@@ -0,0 +1,37 @@
+// 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`.
+
+@_spi(JSObject_id) import JavaScriptKit
+
+@_extern(wasm, module: "bjs", name: "return_string")
+private func _return_string(_ ptr: UnsafePointer<UInt8>?, _ len: Int32)
+@_extern(wasm, module: "bjs", name: "init_memory")
+private func _init_memory(_ sourceId: Int32, _ ptr: UnsafeMutablePointer<UInt8>?)
+
+@_extern(wasm, module: "bjs", name: "swift_js_retain")
+private func _swift_js_retain(_ ptr: Int32) -> Int32
+@_extern(wasm, module: "bjs", name: "swift_js_throw")
+private func _swift_js_throw(_ id: Int32)
+
+@_expose(wasm, "bjs_throwsSomething")
+@_cdecl("bjs_throwsSomething")
+public func _bjs_throwsSomething() -> Void {
+    do {
+        try throwsSomething()
+    } catch let error {
+        if let error = error.thrownValue.object {
+            withExtendedLifetime(error) {
+                _swift_js_throw(Int32(bitPattern: $0.id))
+            }
+        } else {
+            let jsError = JSError(message: String(describing: error))
+            withExtendedLifetime(jsError.jsObject) {
+                _swift_js_throw(Int32(bitPattern: $0.id))
+            }
+        }
+        return
+    }
+}
\ No newline at end of file
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/VoidParameterVoidReturn.json b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/VoidParameterVoidReturn.json
index f82cdb82..96f875ab 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/VoidParameterVoidReturn.json
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/VoidParameterVoidReturn.json
@@ -5,6 +5,10 @@
   "functions" : [
     {
       "abiName" : "bjs_check",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "check",
       "parameters" : [
 
diff --git a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/VoidParameterVoidReturn.swift b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/VoidParameterVoidReturn.swift
index a500740c..0fc0e157 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/VoidParameterVoidReturn.swift
+++ b/Plugins/BridgeJS/Tests/BridgeJSToolTests/__Snapshots__/ExportSwiftTests/VoidParameterVoidReturn.swift
@@ -13,6 +13,8 @@ private func _init_memory(_ sourceId: Int32, _ ptr: UnsafeMutablePointer<UInt8>?
 
 @_extern(wasm, module: "bjs", name: "swift_js_retain")
 private func _swift_js_retain(_ ptr: Int32) -> Int32
+@_extern(wasm, module: "bjs", name: "swift_js_throw")
+private func _swift_js_throw(_ id: Int32)
 
 @_expose(wasm, "bjs_check")
 @_cdecl("bjs_check")
diff --git a/Tests/BridgeJSRuntimeTests/ExportAPITests.swift b/Tests/BridgeJSRuntimeTests/ExportAPITests.swift
index e113a514..2a5ae610 100644
--- a/Tests/BridgeJSRuntimeTests/ExportAPITests.swift
+++ b/Tests/BridgeJSRuntimeTests/ExportAPITests.swift
@@ -32,6 +32,14 @@ func runJsWorks() -> Void
     return v
 }
 
+struct TestError: Error {
+    let message: String
+}
+
+@JS func throwsSwiftError() throws(JSException) -> Void {
+    throw JSException(JSError(message: "TestError").jsValue)
+}
+
 @JS class Greeter {
     var name: String
 
diff --git a/Tests/BridgeJSRuntimeTests/Generated/ExportSwift.swift b/Tests/BridgeJSRuntimeTests/Generated/ExportSwift.swift
index 28514c8e..81202c56 100644
--- a/Tests/BridgeJSRuntimeTests/Generated/ExportSwift.swift
+++ b/Tests/BridgeJSRuntimeTests/Generated/ExportSwift.swift
@@ -13,6 +13,8 @@ private func _init_memory(_ sourceId: Int32, _ ptr: UnsafeMutablePointer<UInt8>?
 
 @_extern(wasm, module: "bjs", name: "swift_js_retain")
 private func _swift_js_retain(_ ptr: Int32) -> Int32
+@_extern(wasm, module: "bjs", name: "swift_js_throw")
+private func _swift_js_throw(_ id: Int32)
 
 @_expose(wasm, "bjs_roundTripVoid")
 @_cdecl("bjs_roundTripVoid")
@@ -75,6 +77,26 @@ public func _bjs_roundTripJSObject(v: Int32) -> Int32 {
     return _swift_js_retain(Int32(bitPattern: ret.id))
 }
 
+@_expose(wasm, "bjs_throwsSwiftError")
+@_cdecl("bjs_throwsSwiftError")
+public func _bjs_throwsSwiftError() -> Void {
+    do {
+        try throwsSwiftError()
+    } catch let error {
+        if let error = error.thrownValue.object {
+            withExtendedLifetime(error) {
+                _swift_js_throw(Int32(bitPattern: $0.id))
+            }
+        } else {
+            let jsError = JSError(message: String(describing: error))
+            withExtendedLifetime(jsError.jsObject) {
+                _swift_js_throw(Int32(bitPattern: $0.id))
+            }
+        }
+        return
+    }
+}
+
 @_expose(wasm, "bjs_takeGreeter")
 @_cdecl("bjs_takeGreeter")
 public func _bjs_takeGreeter(g: UnsafeMutableRawPointer, nameBytes: Int32, nameLen: Int32) -> Void {
diff --git a/Tests/BridgeJSRuntimeTests/Generated/JavaScript/ExportSwift.json b/Tests/BridgeJSRuntimeTests/Generated/JavaScript/ExportSwift.json
index d72c17b9..cd87f654 100644
--- a/Tests/BridgeJSRuntimeTests/Generated/JavaScript/ExportSwift.json
+++ b/Tests/BridgeJSRuntimeTests/Generated/JavaScript/ExportSwift.json
@@ -3,6 +3,10 @@
     {
       "constructor" : {
         "abiName" : "bjs_Greeter_init",
+        "effects" : {
+          "isAsync" : false,
+          "isThrows" : false
+        },
         "parameters" : [
           {
             "label" : "name",
@@ -18,6 +22,10 @@
       "methods" : [
         {
           "abiName" : "bjs_Greeter_greet",
+          "effects" : {
+            "isAsync" : false,
+            "isThrows" : false
+          },
           "name" : "greet",
           "parameters" : [
 
@@ -30,6 +38,10 @@
         },
         {
           "abiName" : "bjs_Greeter_changeName",
+          "effects" : {
+            "isAsync" : false,
+            "isThrows" : false
+          },
           "name" : "changeName",
           "parameters" : [
             {
@@ -55,6 +67,10 @@
   "functions" : [
     {
       "abiName" : "bjs_roundTripVoid",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "roundTripVoid",
       "parameters" : [
 
@@ -67,6 +83,10 @@
     },
     {
       "abiName" : "bjs_roundTripInt",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "roundTripInt",
       "parameters" : [
         {
@@ -87,6 +107,10 @@
     },
     {
       "abiName" : "bjs_roundTripFloat",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "roundTripFloat",
       "parameters" : [
         {
@@ -107,6 +131,10 @@
     },
     {
       "abiName" : "bjs_roundTripDouble",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "roundTripDouble",
       "parameters" : [
         {
@@ -127,6 +155,10 @@
     },
     {
       "abiName" : "bjs_roundTripBool",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "roundTripBool",
       "parameters" : [
         {
@@ -147,6 +179,10 @@
     },
     {
       "abiName" : "bjs_roundTripString",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "roundTripString",
       "parameters" : [
         {
@@ -167,6 +203,10 @@
     },
     {
       "abiName" : "bjs_roundTripSwiftHeapObject",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "roundTripSwiftHeapObject",
       "parameters" : [
         {
@@ -187,6 +227,10 @@
     },
     {
       "abiName" : "bjs_roundTripJSObject",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "roundTripJSObject",
       "parameters" : [
         {
@@ -205,8 +249,28 @@
         }
       }
     },
+    {
+      "abiName" : "bjs_throwsSwiftError",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : true
+      },
+      "name" : "throwsSwiftError",
+      "parameters" : [
+
+      ],
+      "returnType" : {
+        "void" : {
+
+        }
+      }
+    },
     {
       "abiName" : "bjs_takeGreeter",
+      "effects" : {
+        "isAsync" : false,
+        "isThrows" : false
+      },
       "name" : "takeGreeter",
       "parameters" : [
         {
diff --git a/Tests/prelude.mjs b/Tests/prelude.mjs
index c79feb2a..1bc5bdba 100644
--- a/Tests/prelude.mjs
+++ b/Tests/prelude.mjs
@@ -105,6 +105,13 @@ function BridgeJSRuntimeTests_runJsWorks(instance, exports) {
 
     const anyObject = {};
     assert.equal(exports.roundTripJSObject(anyObject), anyObject);
+
+    try {
+        exports.throwsSwiftError();
+        assert.fail("Expected error");
+    } catch (error) {
+        assert.equal(error.message, "TestError");
+    }
 }
 
 function setupTestGlobals(global) {