BridgeJS: Use @JS types from other modules in the same package

Author: wfltaylor

Benchmarks/Sources/Generated/JavaScript/BridgeJS.json

@@ -3415,5 +3415,8 @@
       }
     ]
   },
-  "moduleName" : "Benchmarks"
+  "moduleName" : "Benchmarks",
+  "usedExternalModules" : [
+
+  ]
 }

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")
+            ]
+        ),
+    ]
+)

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`.

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()
+    }
+}

Examples/MultiModule/Sources/Core/bridge-js.config.json

@@ -0,0 +1 @@
+{}

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)
+}

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>

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);

Examples/PlayBridgeJS/Sources/PlayBridgeJS/Generated/JavaScript/BridgeJS.json

@@ -300,5 +300,8 @@
       }
     ]
   },
-  "moduleName" : "PlayBridgeJS"
+  "moduleName" : "PlayBridgeJS",
+  "usedExternalModules" : [
+
+  ]
 }

Plugins/BridgeJS/Sources/BridgeJSBuildPlugin/BridgeJSBuildPlugin.swift

@@ -20,6 +20,7 @@ struct BridgeJSBuildPlugin: BuildToolPlugin {
 
     private func createGenerateCommand(context: PluginContext, target: SwiftSourceModuleTarget) throws -> Command {
         let outputSwiftPath = context.pluginWorkDirectoryURL.appending(path: "BridgeJS.swift")
+        let outputSkeletonPath = context.pluginWorkDirectoryURL.appending(path: "JavaScript/BridgeJS.json")
 
         let inputSwiftFiles = target.sourceFiles.filter {
             !$0.url.path.hasPrefix(context.pluginWorkDirectoryURL.path + "/")
@@ -63,6 +64,14 @@ struct BridgeJSBuildPlugin: BuildToolPlugin {
             ])
         }
 
+        for skeleton in dependencySkeletons(context: context, target: target) {
+            arguments.append(contentsOf: [
+                "--dependency-skeleton",
+                "\(skeleton.moduleName)=\(skeleton.url.path)",
+            ])
+            inputFiles.append(skeleton.url)
+        }
+
         let allSwiftFiles = inputSwiftFiles + pluginGeneratedSwiftFiles
         arguments.append(contentsOf: allSwiftFiles.map(\.path))
 
@@ -71,8 +80,47 @@ struct BridgeJSBuildPlugin: BuildToolPlugin {
             executable: try context.tool(named: "BridgeJSTool").url,
             arguments: arguments,
             inputFiles: inputFiles,
-            outputFiles: [outputSwiftPath]
+            outputFiles: [outputSwiftPath, outputSkeletonPath]
         )
     }
+
+    private struct DependencySkeleton {
+        let moduleName: String
+        let url: 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
+            )
+            skeletons.append(DependencySkeleton(moduleName: swiftTarget.name, url: skeletonURL))
+        }
+        return skeletons
+    }
 }
 #endif