DRY’d the throws diagnostics and kept behavior: added shared helpers for JSException notes and clause construction, reused in JSFunction/JSSetter. JSSetter now uses its own propagation note text via the helper. All macro tests still green: swift test --package-path ./Plugins/BridgeJS --filter BridgeJSMacrosTests.

If you want, I can similarly centralize any other repeated note/fix-it strings or run the full plugin suite.

Author: kateinoigakukun

Plugins/BridgeJS/Sources/BridgeJSMacros/JSMacroSupport.swift

@@ -29,6 +29,11 @@ struct JSMacroFixItMessage: FixItMessage {
     var fixItID: MessageID { MessageID(domain: "JavaScriptKitMacros", id: message) }
 }
 
+enum JSMacroText {
+    static let jsExceptionPropagation = "@JSFunction must propagate JavaScript errors as JSException."
+    static let jsSetterExceptionPropagation = "@JSSetter must propagate JavaScript errors as JSException."
+}
+
 struct JSMacroWarningMessage: DiagnosticMessage {
     let message: String
     var diagnosticID: MessageID { MessageID(domain: "JavaScriptKitMacros", id: message) }
@@ -211,28 +216,15 @@ enum JSMacroHelper {
         guard !isJSException else { return }
         guard !isAllowedGenericError else { return }
 
-        let throwsSpecifier = throwsClause.throwsSpecifier.with(\.trailingTrivia, .spaces(0))
-        let leftParen = throwsClause.leftParen ?? .leftParenToken()
-        let rightParen = (throwsClause.rightParen ?? .rightParenToken())
-            .with(\.trailingTrivia, throwsClause.rightParen?.trailingTrivia ?? .space)
-        let newThrowsClause = throwsClause
-            .with(\.throwsSpecifier, throwsSpecifier)
-            .with(\.leftParen, leftParen)
-            .with(\.type, TypeSyntax(IdentifierTypeSyntax(name: .identifier("JSException"))))
-            .with(\.rightParen, rightParen)
+        let newThrowsClause = jsExceptionThrowsClause(from: throwsClause)
 
         let fixIt = FixIt(
             message: JSMacroFixItMessage(message: "Declare throws(JSException)"),
             changes: [.replace(oldNode: Syntax(throwsClause), newNode: Syntax(newThrowsClause))]
         )
 
         var notes: [Note] = [
-            Note(
-                node: node,
-                message: JSMacroNoteMessage(
-                    message: "@JSFunction must propagate JavaScript errors as JSException."
-                )
-            )
+            jsExceptionPropagationNote(on: node)
         ]
         notes.append(contentsOf: additionalNotes)
 
@@ -276,4 +268,29 @@ enum JSMacroHelper {
         guard let base = setterPropertyBase(from: firstParameter) else { return nil }
         return "set" + capitalizingFirstLetter(base)
     }
+
+    /// Build a typed throws(JSException) clause preserving trivia when possible.
+    static func jsExceptionThrowsClause(from throwsClause: ThrowsClauseSyntax?) -> ThrowsClauseSyntax {
+        let throwsSpecifier = (throwsClause?.throwsSpecifier ?? .keyword(.throws, leadingTrivia: .space))
+            .with(\.trailingTrivia, .spaces(0))
+        let leftParen = throwsClause?.leftParen ?? .leftParenToken()
+        let rightParen = (throwsClause?.rightParen ?? .rightParenToken())
+            .with(\.trailingTrivia, throwsClause?.rightParen?.trailingTrivia ?? .space)
+
+        return ThrowsClauseSyntax(
+            throwsSpecifier: throwsSpecifier,
+            leftParen: leftParen,
+            type: TypeSyntax(IdentifierTypeSyntax(name: .identifier("JSException"))),
+            rightParen: rightParen
+        )
+    }
+
+    static func jsExceptionPropagationNote(on node: Syntax, message: String = JSMacroText.jsExceptionPropagation) -> Note {
+        Note(
+            node: node,
+            message: JSMacroNoteMessage(
+                message: message
+            )
+        )
+    }
 }

Plugins/BridgeJS/Sources/BridgeJSMacros/JSSetterMacro.swift

@@ -195,14 +195,8 @@ extension JSSetterMacro: BodyMacro {
         let hasAnyThrows = functionDecl.signature.effectSpecifiers?.throwsClause != nil
 
         if !hasTypedJSException {
-            let existingLeadingTrivia = functionDecl.signature.effectSpecifiers?.throwsClause?.throwsSpecifier
-                .leadingTrivia
-            let throwsLeadingTrivia = existingLeadingTrivia ?? .space
-            let throwsClause = ThrowsClauseSyntax(
-                throwsSpecifier: .keyword(.throws, leadingTrivia: throwsLeadingTrivia),
-                leftParen: .leftParenToken(),
-                type: IdentifierTypeSyntax(name: .identifier("JSException")),
-                rightParen: .rightParenToken()
+            let throwsClause = JSMacroHelper.jsExceptionThrowsClause(
+                from: functionDecl.signature.effectSpecifiers?.throwsClause
             )
             let newEffects = (functionDecl.signature.effectSpecifiers
                 ?? FunctionEffectSpecifiersSyntax(asyncSpecifier: nil, throwsClause: nil))
@@ -213,11 +207,9 @@ extension JSSetterMacro: BodyMacro {
                 changes: [.replace(oldNode: Syntax(functionDecl.signature), newNode: Syntax(newSignature))]
             )
             var notes: [Note] = [
-                Note(
-                    node: Syntax(functionDecl),
-                    message: JSMacroNoteMessage(
-                        message: "@JSSetter must propagate JavaScript errors as JSException."
-                    )
+                JSMacroHelper.jsExceptionPropagationNote(
+                    on: Syntax(functionDecl),
+                    message: JSMacroText.jsSetterExceptionPropagation
                 )
             ]
             if let wrapperNote {