swiftwasm · kateinoigakukun · Apr 30, 2026 · Apr 28, 2026 · Apr 28, 2026 · Apr 29, 2026
diff --git a/Benchmarks/Sources/Generated/JavaScript/BridgeJS.json b/Benchmarks/Sources/Generated/JavaScript/BridgeJS.json
@@ -3415,5 +3415,8 @@
       }
     ]
   },
-  "moduleName" : "Benchmarks"
+  "moduleName" : "Benchmarks",
+  "usedExternalModules" : [
+
+  ]
 }
diff --git a/Examples/MultiModule/Package.swift b/Examples/MultiModule/Package.swift
@@ -0,0 +1,38 @@
+// swift-tools-version:6.0
+
+import PackageDescription
+
+let package = Package(
+    name: "MultiModule",
+    platforms: [
+        .macOS(.v14)
+    ],
+    dependencies: [.package(name: "JavaScriptKit", path: "../../")],
+    targets: [
+        .target(
+            name: "Core",
+            dependencies: [
+                "JavaScriptKit"
+            ],
+            swiftSettings: [
+                .enableExperimentalFeature("Extern")
+            ],
+            plugins: [
+                .plugin(name: "BridgeJS", package: "JavaScriptKit")
+            ]
+        ),
+        .executableTarget(
+            name: "MultiModule",
+            dependencies: [
+                "Core",
+                "JavaScriptKit",
+            ],
+            swiftSettings: [
+                .enableExperimentalFeature("Extern")
+            ],
+            plugins: [
+                .plugin(name: "BridgeJS", package: "JavaScriptKit")
+            ]
+        ),
+    ]
+)
diff --git a/Examples/MultiModule/README.md b/Examples/MultiModule/README.md
@@ -0,0 +1,17 @@
+# MultiModule Example
+
+This example demonstrates using `@JS` types defined in one module (`Core`) from another module (`App`) within the same Swift package.
+
+## Building and Running
+
+1. Build the project:
+   ```sh
+   swift package --swift-sdk $SWIFT_SDK_ID js --use-cdn
+   ```
+
+2. Serve the files:
+   ```sh
+   npx serve
+   ```
+
+Then open your browser to `http://localhost:3000`.
diff --git a/Examples/MultiModule/Sources/Core/Vector3D.swift b/Examples/MultiModule/Sources/Core/Vector3D.swift
@@ -0,0 +1,17 @@
+import JavaScriptKit
+
+@JS public struct Vector3D {
+    public let x: Double
+    public let y: Double
+    public let z: Double
+
+    @JS public init(x: Double, y: Double, z: Double) {
+        self.x = x
+        self.y = y
+        self.z = z
+    }
+
+    @JS public func magnitude() -> Double {
+        (x * x + y * y + z * z).squareRoot()
+    }
+}
diff --git a/Examples/MultiModule/Sources/Core/bridge-js.config.json b/Examples/MultiModule/Sources/Core/bridge-js.config.json
@@ -0,0 +1 @@
+{}
diff --git a/Examples/MultiModule/Sources/MultiModule/bridge-js.config.json b/Examples/MultiModule/Sources/MultiModule/bridge-js.config.json
@@ -0,0 +1 @@
+{}
diff --git a/Examples/MultiModule/Sources/MultiModule/main.swift b/Examples/MultiModule/Sources/MultiModule/main.swift
@@ -0,0 +1,6 @@
+import Core
+import JavaScriptKit
+
+@JS public func currentVelocity() -> Vector3D {
+    Vector3D(x: 0.1, y: 0.2, z: 0.3)
+}
diff --git a/Examples/MultiModule/index.html b/Examples/MultiModule/index.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+  <title>MultiModule Example</title>
+</head>
+
+<body>
+  <script type="module" src="index.js"></script>
+</body>
+
+</html>
diff --git a/Examples/MultiModule/index.js b/Examples/MultiModule/index.js
@@ -0,0 +1,10 @@
+import { init } from "./.build/plugins/PackageToJS/outputs/Package/index.js";
+const { exports } = await init({});
+
+const velocity = exports.currentVelocity();
+
+const output = document.createElement("pre");
+output.innerText =
+    `currentVelocity() = (${velocity.x}, ${velocity.y}, ${velocity.z})\n`
+    + `magnitude = ${velocity.magnitude()}`;
+document.body.appendChild(output);
diff --git a/Examples/PlayBridgeJS/Sources/PlayBridgeJS/Generated/JavaScript/BridgeJS.json b/Examples/PlayBridgeJS/Sources/PlayBridgeJS/Generated/JavaScript/BridgeJS.json
@@ -300,5 +300,8 @@
       }
     ]
   },
-  "moduleName" : "PlayBridgeJS"
+  "moduleName" : "PlayBridgeJS",
+  "usedExternalModules" : [
+
+  ]
 }
diff --git a/Examples/PlayBridgeJS/Sources/PlayBridgeJS/main.swift b/Examples/PlayBridgeJS/Sources/PlayBridgeJS/main.swift
@@ -45,7 +45,12 @@ import class Foundation.JSONDecoder
     func _update(swiftSource: String, dtsSource: String) throws -> PlayBridgeJSOutput {
         let moduleName = "Playground"
 
-        let swiftToSkeleton = SwiftToSkeleton(progress: .silent, moduleName: moduleName, exposeToGlobal: false)
+        let swiftToSkeleton = SwiftToSkeleton(
+            progress: .silent,
+            moduleName: moduleName,
+            exposeToGlobal: false,
+            externalModuleIndex: .empty
+        )
         swiftToSkeleton.addSourceFile(Parser.parse(source: swiftSource), inputFilePath: "Playground.swift")
 
         let ts2swift = try createTS2Swift()

diff --git a/Plugins/BridgeJS/Sources/BridgeJSBuildPlugin/BridgeJSBuildPlugin.swift b/Plugins/BridgeJS/Sources/BridgeJSBuildPlugin/BridgeJSBuildPlugin.swift
@@ -63,6 +63,19 @@ struct BridgeJSBuildPlugin: BuildToolPlugin {
             ])
         }
 
+        for skeleton in dependencySkeletons(context: context, target: target) {
+            arguments.append(contentsOf: [
+                "--dependency-skeleton",
+                "\(skeleton.moduleName)=\(skeleton.skeletonURL.path)",
+            ])
+            // We have to use the Swift file, not the skeleton, as the input file,
+            // since we can’t make the skeleton file an output file without it being
+            // treated as a resource by the build system (and thus included in the
+            // resource bundle). We need to use something as the inputFile to maintain
+            // correct ordering.
+            inputFiles.append(skeleton.bridgeJSSwiftURL)
+        }
+
         let allSwiftFiles = inputSwiftFiles + pluginGeneratedSwiftFiles
         arguments.append(contentsOf: allSwiftFiles.map(\.path))
 
@@ -74,5 +87,56 @@ struct BridgeJSBuildPlugin: BuildToolPlugin {
             outputFiles: [outputSwiftPath]
         )
     }
+
+    private struct DependencySkeleton {
+        let moduleName: String
+        let skeletonURL: URL
+        let bridgeJSSwiftURL: URL
+    }
+
+    /// We only read skeletons from dependencies with a `bridge-js.config.json` file.
+    /// For the build system to correctly order the plugins, we need to set the skeleton
+    /// files as input. However, I don’t think we have enough information here to determine
+    /// whether the plugin which generates this is applied to the dependency, so we use
+    /// the presence of `bridge-js.config.json` instead.
+    private func dependencySkeletons(
+        context: PluginContext,
+        target: SwiftSourceModuleTarget
+    ) -> [DependencySkeleton] {
+        let localTargets: [SwiftSourceModuleTarget] = target.recursiveTargetDependencies
+            .compactMap { dependency in
+                guard
+                    let swiftTarget = dependency as? SwiftSourceModuleTarget,
+                    context.package.targets.contains(where: { $0.id == swiftTarget.id }),
+                    FileManager.default.fileExists(atPath: pathToConfigFile(target: swiftTarget).path)
+                else {
+                    return nil
+                }
+                return swiftTarget
+            }
+
+        var skeletons: [DependencySkeleton] = []
+        var seenTargetNames = Set<String>()
+        for swiftTarget in localTargets where seenTargetNames.insert(swiftTarget.name).inserted {
+            let skeletonURL = BridgeJSPluginPaths.skeletonURL(
+                targetName: swiftTarget.name,
+                packageID: context.package.id,
+                buildPluginWorkDirectoryURL: context.pluginWorkDirectoryURL
+            )
+            let bridgeJSSwiftURL = BridgeJSPluginPaths.bridgeJSSwiftURL(
+                targetName: swiftTarget.name,
+                packageID: context.package.id,
+                buildPluginWorkDirectoryURL: context.pluginWorkDirectoryURL
+            )
+            skeletons.append(
+                DependencySkeleton(
+                    moduleName: swiftTarget.name,
+                    skeletonURL: skeletonURL,
+                    bridgeJSSwiftURL: bridgeJSSwiftURL
+                )
+            )
+        }
+        return skeletons
+    }
 }
 #endif
diff --git a/Plugins/BridgeJS/Sources/BridgeJSBuildPlugin/BridgeJSPluginUtilities b/Plugins/BridgeJS/Sources/BridgeJSBuildPlugin/BridgeJSPluginUtilities
@@ -0,0 +1 @@
+../BridgeJSPluginUtilities
diff --git a/Plugins/BridgeJS/Sources/BridgeJSCommandPlugin/BridgeJSCommandPlugin.swift b/Plugins/BridgeJS/Sources/BridgeJSCommandPlugin/BridgeJSCommandPlugin.swift
@@ -74,28 +74,62 @@ struct BridgeJSCommandPlugin: CommandPlugin {
 }
 
 extension BridgeJSCommandPlugin.Context {
-    func runOnTargets(
-        remainingArguments: [String],
-        where predicate: (SwiftSourceModuleTarget) -> Bool
-    ) throws {
+    private func collectBridgeJSTargets() -> [String: SwiftSourceModuleTarget] {
+        var bridgeJSTargets: [String: SwiftSourceModuleTarget] = [:]
         for target in context.package.targets {
-            guard let target = target as? SwiftSourceModuleTarget else {
+            guard
+                let swiftTarget = target as? SwiftSourceModuleTarget,
+                FileManager.default.fileExists(
+                    atPath: swiftTarget.directoryURL.appending(path: "bridge-js.config.json").path
+                )
+            else {
                 continue
             }
-            let configFilePath = target.directoryURL.appending(path: "bridge-js.config.json")
-            if !FileManager.default.fileExists(atPath: configFilePath.path) {
-                printVerbose("No bridge-js.config.json found for \(target.name), skipping...")
-                continue
+            bridgeJSTargets[swiftTarget.name] = swiftTarget
+        }
+        return bridgeJSTargets
+    }
+
+    private func targetsInDependencyOrder(
+        _ bridgeJSTargets: [String: SwiftSourceModuleTarget]
+    ) -> [SwiftSourceModuleTarget] {
+        var visitedTargetNames = Set<String>()
+        var orderedTargets: [SwiftSourceModuleTarget] = []
+        func visit(_ target: SwiftSourceModuleTarget) {
+            if !visitedTargetNames.insert(target.name).inserted {
+                return
             }
-            guard predicate(target) else {
-                continue
+            for dependency in target.recursiveTargetDependencies {
+                if let dependencyTarget = bridgeJSTargets[dependency.name] {
+                    visit(dependencyTarget)
+                }
             }
-            try runSingleTarget(target: target, remainingArguments: remainingArguments)
+            orderedTargets.append(target)
+        }
+        for target in bridgeJSTargets.values.sorted(by: { $0.name < $1.name }) {
+            visit(target)
+        }
+        return orderedTargets
+    }
+
+    func runOnTargets(
+        remainingArguments: [String],
+        where predicate: (SwiftSourceModuleTarget) -> Bool
+    ) throws {
+        let allBridgeJSTargets = collectBridgeJSTargets()
+        let requestedTargets = allBridgeJSTargets.filter { predicate($1) }
+        for target in targetsInDependencyOrder(requestedTargets) {
+            try runSingleTarget(
+                target: target,
+                bridgeJSTargets: allBridgeJSTargets,
+                remainingArguments: remainingArguments
+            )
         }
     }
 
     private func runSingleTarget(
         target: SwiftSourceModuleTarget,
+        bridgeJSTargets: [String: SwiftSourceModuleTarget],
         remainingArguments: [String]
     ) throws {
         printStderr("Generating bridge code for \(target.name)...")
@@ -126,6 +160,25 @@ extension BridgeJSCommandPlugin.Context {
             ])
         }
 
+        for dependency in target.recursiveTargetDependencies {
+            guard let dependencyTarget = bridgeJSTargets[dependency.name] else { continue }
+            let dependencySkeletonPath = dependencyTarget.directoryURL
+                .appending(path: "Generated/JavaScript/BridgeJS.json")
+            guard FileManager.default.fileExists(atPath: dependencySkeletonPath.path) else {
+                throw BridgeJSCommandPluginError(
+                    """
+                    Dependency '\(dependencyTarget.name)' is configured for BridgeJS, but its AOT skeleton has not been generated yet. \
+                    Run `swift package bridge-js --target \(dependencyTarget.name)` to generate it first, \
+                    or run without `--target` to process in dependency order.
+                    """
+                )
+            }
+            generateArguments.append(contentsOf: [
+                "--dependency-skeleton",
+                "\(dependencyTarget.name)=\(dependencySkeletonPath.path)",
+            ])
+        }
+
         generateArguments.append(
             contentsOf: target.sourceFiles.filter {
                 !$0.url.path.hasPrefix(generatedDirectory.path + "/")
@@ -162,6 +215,14 @@ private func printStderr(_ message: String) {
     fputs(message + "\n", stderr)
 }
 
+struct BridgeJSCommandPluginError: Error, CustomStringConvertible {
+    let description: String
+
+    init(_ message: String) {
+        self.description = message
+    }
+}
+
 extension SwiftSourceModuleTarget {
     func hasDependency(named name: String) -> Bool {
         return dependencies.contains(where: {