Added a BridgeJS runtime import test for TS string enums.

- Updated `Tests/BridgeJSRuntimeTests/bridge-js.d.ts` with `FeatureFlag` + `jsRoundTripFeatureFlag`.
- Added JS implementation in `Tests/prelude.mjs`.
- Added XCTest in `Tests/BridgeJSRuntimeTests/ImportAPITests.swift` (`testRoundTripFeatureFlag`).
- Regenerated runtime fixtures under `Tests/BridgeJSRuntimeTests/Generated/` (via `BridgeJSTool generate`).
- Verified runtime: `make unittest SWIFT_SDK_ID=DEVELOPMENT-SNAPSHOT+MAIN-wasm32-unknown-wasip1-threads` (passes).

Author: kateinoigakukun

Plugins/BridgeJS/Sources/TS2Swift/JavaScript/src/processor.js

@@ -251,35 +251,6 @@ export class TypeProcessor {
             return;
         }
 
-        /**
-         * Convert a TypeScript enum member name into a valid Swift identifier.
-         * @param {string} name
-         * @returns {string}
-         */
-        const toSwiftCaseName = (name) => {
-            const swiftIdentifierRegex = /^[_\p{ID_Start}][\p{ID_Continue}\u{200C}\u{200D}]*$/u;
-            let result = "";
-            for (const ch of name) {
-                const isIdentifierChar = /^[_\p{ID_Continue}\u{200C}\u{200D}]$/u.test(ch);
-                result += isIdentifierChar ? ch : "_";
-            }
-            if (!result) result = "_case";
-            if (!/^[_\p{ID_Start}]$/u.test(result[0])) {
-                result = "_" + result;
-            }
-            if (!swiftIdentifierRegex.test(result)) {
-                result = result.replace(/[^_\p{ID_Continue}\u{200C}\u{200D}]/gu, "_");
-                if (!result) result = "_case";
-                if (!/^[_\p{ID_Start}]$/u.test(result[0])) {
-                    result = "_" + result;
-                }
-            }
-            if (isSwiftKeyword(result)) {
-                result = result + "_";
-            }
-            return result;
-        };
-
         /** @type {{ name: string, raw: string }[]} */
         const stringMembers = [];
         /** @type {{ name: string, raw: number }[]} */
@@ -291,7 +262,7 @@ export class TypeProcessor {
         for (const member of members) {
             const rawMemberName = member.name.getText();
             const unquotedName = rawMemberName.replace(/^["']|["']$/g, "");
-            const swiftCaseNameBase = toSwiftCaseName(unquotedName);
+            const swiftCaseNameBase = makeValidSwiftIdentifier(unquotedName, { emptyFallback: "_case" });
 
             if (member.initializer && ts.isStringLiteral(member.initializer)) {
                 stringMembers.push({ name: swiftCaseNameBase, raw: member.initializer.text });
@@ -811,3 +782,33 @@ export function isValidSwiftDeclName(name) {
     const swiftIdentifierRegex = /^[_\p{ID_Start}][\p{ID_Continue}\u{200C}\u{200D}]*$/u;
     return swiftIdentifierRegex.test(name);
 }
+
+/**
+ * Convert an arbitrary string into a valid Swift identifier.
+ * @param {string} name
+ * @param {{ emptyFallback?: string }} options
+ * @returns {string}
+ */
+function makeValidSwiftIdentifier(name, options = {}) {
+    const emptyFallback = options.emptyFallback ?? "_";
+    let result = "";
+    for (const ch of name) {
+        const isIdentifierChar = /^[_\p{ID_Continue}\u{200C}\u{200D}]$/u.test(ch);
+        result += isIdentifierChar ? ch : "_";
+    }
+    if (!result) result = emptyFallback;
+    if (!/^[_\p{ID_Start}]$/u.test(result[0])) {
+        result = "_" + result;
+    }
+    if (!isValidSwiftDeclName(result)) {
+        result = result.replace(/[^_\p{ID_Continue}\u{200C}\u{200D}]/gu, "_");
+        if (!result) result = emptyFallback;
+        if (!/^[_\p{ID_Start}]$/u.test(result[0])) {
+            result = "_" + result;
+        }
+    }
+    if (isSwiftKeyword(result)) {
+        result = result + "_";
+    }
+    return result;
+}

Tests/BridgeJSRuntimeTests/Generated/BridgeJS.Macros.swift

@@ -22,6 +22,14 @@
 
 @JSFunction func jsThrowOrString(_ shouldThrow: Bool) throws (JSException) -> String
 
+enum FeatureFlag: String {
+    case foo = "foo"
+    case bar = "bar"
+}
+extension FeatureFlag: _BridgedSwiftEnumNoPayload {}
+
+@JSFunction func jsRoundTripFeatureFlag(_ flag: FeatureFlag) throws (JSException) -> FeatureFlag
+
 @JSClass struct JsGreeter {
     @JSGetter var name: String
     @JSSetter func setName(_ value: String) throws (JSException)

Tests/BridgeJSRuntimeTests/Generated/BridgeJS.swift

@@ -6307,6 +6307,24 @@ func _$jsThrowOrString(_ shouldThrow: Bool) throws(JSException) -> String {
     return String.bridgeJSLiftReturn(ret)
 }
 
+#if arch(wasm32)
+@_extern(wasm, module: "BridgeJSRuntimeTests", name: "bjs_jsRoundTripFeatureFlag")
+fileprivate func bjs_jsRoundTripFeatureFlag(_ flag: Int32) -> Int32
+#else
+fileprivate func bjs_jsRoundTripFeatureFlag(_ flag: Int32) -> Int32 {
+    fatalError("Only available on WebAssembly")
+}
+#endif
+
+func _$jsRoundTripFeatureFlag(_ flag: FeatureFlag) throws(JSException) -> FeatureFlag {
+    let flagValue = flag.bridgeJSLowerParameter()
+    let ret = bjs_jsRoundTripFeatureFlag(flagValue)
+    if let error = _swift_js_take_exception() {
+        throw error
+    }
+    return FeatureFlag.bridgeJSLiftReturn(ret)
+}
+
 #if arch(wasm32)
 @_extern(wasm, module: "BridgeJSRuntimeTests", name: "bjs_runAsyncWorks")
 fileprivate func bjs_runAsyncWorks() -> Int32

Tests/BridgeJSRuntimeTests/Generated/JavaScript/BridgeJS.json

@@ -9070,6 +9070,26 @@
               }
             }
           },
+          {
+            "name" : "jsRoundTripFeatureFlag",
+            "parameters" : [
+              {
+                "name" : "flag",
+                "type" : {
+                  "rawValueEnum" : {
+                    "_0" : "FeatureFlag",
+                    "_1" : "String"
+                  }
+                }
+              }
+            ],
+            "returnType" : {
+              "rawValueEnum" : {
+                "_0" : "FeatureFlag",
+                "_1" : "String"
+              }
+            }
+          },
           {
             "name" : "runAsyncWorks",
             "parameters" : [

Tests/BridgeJSRuntimeTests/ImportAPITests.swift

@@ -35,6 +35,12 @@ class ImportAPITests: XCTestCase {
         }
     }
 
+    func testRoundTripFeatureFlag() throws {
+        for v in [FeatureFlag.foo, .bar] {
+            try XCTAssertEqual(jsRoundTripFeatureFlag(v), v)
+        }
+    }
+
     func ensureThrows<T>(_ f: (Bool) throws(JSException) -> T) throws {
         do {
             _ = try f(true)

Tests/BridgeJSRuntimeTests/bridge-js.d.ts

@@ -7,6 +7,13 @@ export function jsThrowOrNumber(shouldThrow: boolean): number
 export function jsThrowOrBool(shouldThrow: boolean): boolean
 export function jsThrowOrString(shouldThrow: boolean): string
 
+export enum FeatureFlag {
+    foo = "foo",
+    bar = "bar",
+}
+
+export function jsRoundTripFeatureFlag(flag: FeatureFlag): FeatureFlag
+
 export class JsGreeter {
     name: string;
     readonly prefix: string;
@@ -15,4 +22,4 @@ export class JsGreeter {
     changeName(name: string): void;
 }
 
-export function runAsyncWorks(): Promise<void>;
+export function runAsyncWorks(): Promise<void>;

Tests/prelude.mjs

@@ -47,6 +47,9 @@ export async function setupOptions(options, context) {
                     }
                     return "Hello, world!";
                 },
+                "jsRoundTripFeatureFlag": (flag) => {
+                    return flag;
+                },
                 JsGreeter: class {
                     /**
                      * @param {string} name