Add ts2swift Record to Dictionary mapping (#582)

Author: kateinoigakukun

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

@@ -663,6 +663,7 @@ export class TypeProcessor {
      * @private
      */
     visitType(type, node) {
+        const typeArguments = this.getTypeArguments(type);
         if (this.checker.isArrayType(type)) {
             const typeArgs = this.checker.getTypeArguments(type);
             if (typeArgs && typeArgs.length > 0) {
@@ -672,6 +673,11 @@ export class TypeProcessor {
             return "[JSObject]";
         }
 
+        const recordType = this.convertRecordType(type, typeArguments, node);
+        if (recordType) {
+            return recordType;
+        }
+
         // Treat A<B> and A<C> as the same type
         if (isTypeReference(type)) {
             type = type.target;
@@ -760,6 +766,54 @@ export class TypeProcessor {
         return swiftType;
     }
 
+    /**
+     * Convert a `Record<string, T>` TypeScript type into a Swift dictionary type.
+     * Falls back to `JSObject` when keys are not string-compatible or type arguments are missing.
+     * @param {ts.Type} type
+     * @param {ts.Type[]} typeArguments
+     * @param {ts.Node} node
+     * @returns {string | null}
+     * @private
+     */
+    convertRecordType(type, typeArguments, node) {
+        const symbol = type.aliasSymbol ?? type.getSymbol();
+        if (!symbol || symbol.name !== "Record") {
+            return null;
+        }
+        if (typeArguments.length !== 2) {
+            this.diagnosticEngine.print("warning", "Record expects two type arguments", node);
+            return "JSObject";
+        }
+        const [keyType, valueType] = typeArguments;
+        const stringType = this.checker.getStringType();
+        if (!this.checker.isTypeAssignableTo(keyType, stringType)) {
+            this.diagnosticEngine.print(
+                "warning",
+                `Record key type must be assignable to string: ${this.checker.typeToString(keyType)}`,
+                node
+            );
+            return "JSObject";
+        }
+
+        const valueSwiftType = this.visitType(valueType, node);
+        return `[String: ${valueSwiftType}]`;
+    }
+
+    /**
+     * Retrieve type arguments for a given type, including type alias instantiations.
+     * @param {ts.Type} type
+     * @returns {ts.Type[]}
+     * @private
+     */
+    getTypeArguments(type) {
+        if (isTypeReference(type)) {
+            return this.checker.getTypeArguments(type);
+        }
+        // Non-TypeReference alias instantiations store type arguments separately.
+        // @ts-ignore: `aliasTypeArguments` is intentionally accessed for alias instantiations.
+        return type.aliasTypeArguments ?? [];
+    }
+
     /**
      * Derive the type name from a type
      * @param {ts.Type} type - TypeScript type

Plugins/BridgeJS/Sources/TS2Swift/JavaScript/test/__snapshots__/ts2swift.test.js.snap

@@ -251,6 +251,36 @@ exports[`ts2swift > snapshots Swift output for ReExportFrom.d.ts > ReExportFrom
 "
 `;
 
+exports[`ts2swift > snapshots Swift output for RecordDictionary.d.ts > RecordDictionary 1`] = `
+"// 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(Experimental) @_spi(BridgeJS) import JavaScriptKit
+
+@JSFunction func takeRecord(_ value: [String: Double]) throws(JSException) -> Void
+
+@JSFunction func returnRecord() throws(JSException) -> [String: String]
+
+@JSFunction func optionalRecord(_ value: Optional<[String: Bool]>) throws(JSException) -> Optional<[String: Bool]>
+
+@JSFunction func nestedRecord(_ value: [String: [String: Double]]) throws(JSException) -> [String: [String: Double]]
+
+@JSFunction func recordWithArrayValues(_ values: [String: [Double]]) throws(JSException) -> [String: [Double]]
+
+@JSFunction func recordWithObjects(_ values: [String: Optional<Box>]) throws(JSException) -> [String: Optional<Box>]
+
+@JSClass struct Box {
+    @JSGetter var value: Double
+    @JSSetter func setValue(_ value: Double) throws(JSException)
+}
+
+@JSFunction func unsupportedKeyRecord(_ values: JSObject) throws(JSException) -> Void
+"
+`;
+
 exports[`ts2swift > snapshots Swift output for StringEnum.d.ts > StringEnum 1`] = `
 "// NOTICE: This is auto-generated code by BridgeJS from JavaScriptKit,
 // DO NOT EDIT.

Plugins/BridgeJS/Sources/TS2Swift/JavaScript/test/fixtures/RecordDictionary.d.ts

@@ -0,0 +1,17 @@
+export interface Box {
+    value: number;
+}
+
+export function takeRecord(value: Record<string, number>): void;
+
+export function returnRecord(): Record<string, string>;
+
+export function optionalRecord(value: Record<string, boolean> | null): Record<string, boolean> | null;
+
+export function nestedRecord(value: Record<string, Record<string, number>>): Record<string, Record<string, number>>;
+
+export function recordWithArrayValues(values: Record<string, number[]>): Record<string, number[]>;
+
+export function recordWithObjects(values: Record<string, Box | null>): Record<string, Box | null>;
+
+export function unsupportedKeyRecord(values: Record<number, string>): void;