[interop] Add support for Conditional and Predicate Types

web_generator/lib/src/ast/helpers.dart

@@ -259,6 +259,8 @@ Type desugarTypeAliases(Type t) {
   if (t case final ReferredType ref
       when ref.declaration is TypeAliasDeclaration) {
     return desugarTypeAliases((ref.declaration as TypeAliasDeclaration).type);
+  } else if (t case ReferredDeclarationType(type: final actualType)) {
+    return desugarTypeAliases(actualType);
   }
   return t;
 }

web_generator/lib/src/ast/types.dart

@@ -673,48 +673,48 @@ sealed class _UnionOrIntersectionDeclaration extends NamedDeclaration
               dartTypeName ?? typeName,
             _ => t.dartName ?? t.id.name
           };
+          final Expression body;
+          if (desugarTypeAliases(t) == repType) {
+            body = refer('_');
+          } else if (jsTypeAlt.id == t.id) {
+            body = refer('_').asA(type);
+          } else {
+            body = switch (t) {
+              BuiltinType(name: final n) when n == 'int' => refer('_')
+                  .asA(jsTypeAlt.emit(options?.toTypeOptions()))
+                  .property('toDartInt'),
+              BuiltinType(name: final n) when n == 'double' || n == 'num' =>
+                refer('_')
+                    .asA(jsTypeAlt.emit(options?.toTypeOptions()))
+                    .property('toDartDouble'),
+              BuiltinType() => refer('_')
+                  .asA(jsTypeAlt.emit(options?.toTypeOptions()))
+                  .property('toDart'),
+              ReferredType(
+                declaration: final decl,
+                name: final n,
+                url: final url
+              )
+                  when decl is EnumDeclaration =>
+                refer(n, url).property('_').call([
+                  refer('_')
+                      .asA(jsTypeAlt.emit(options?.toTypeOptions()))
+                      .property(decl.baseType is NamedType
+                          ? switch ((decl.baseType as NamedType).name) {
+                              'int' => 'toDartInt',
+                              'num' || 'double' => 'toDartDouble',
+                              _ => 'toDart'
+                            }
+                          : 'toDart')
+                ]),
+              _ => refer('_').asA(jsTypeAlt.emit(options?.toTypeOptions()))
+            };
+          }
           m
             ..type = MethodType.getter
             ..name = 'as${uppercaseFirstLetter(word)}'
             ..returns = type
-            ..body = jsTypeAlt.id == t.id
-                ? refer('_').asA(type).code
-                : switch (t) {
-                    BuiltinType(name: final n) when n == 'int' => refer('_')
-                        .asA(jsTypeAlt.emit(options?.toTypeOptions()))
-                        .property('toDartInt')
-                        .code,
-                    BuiltinType(name: final n)
-                        when n == 'double' || n == 'num' =>
-                      refer('_')
-                          .asA(jsTypeAlt.emit(options?.toTypeOptions()))
-                          .property('toDartDouble')
-                          .code,
-                    BuiltinType() => refer('_')
-                        .asA(jsTypeAlt.emit(options?.toTypeOptions()))
-                        .property('toDart')
-                        .code,
-                    ReferredType(
-                      declaration: final decl,
-                      name: final n,
-                      url: final url
-                    )
-                        when decl is EnumDeclaration =>
-                      refer(n, url).property('_').call([
-                        refer('_')
-                            .asA(jsTypeAlt.emit(options?.toTypeOptions()))
-                            .property(decl.baseType is NamedType
-                                ? switch ((decl.baseType as NamedType).name) {
-                                    'int' => 'toDartInt',
-                                    'num' || 'double' => 'toDartDouble',
-                                    _ => 'toDart'
-                                  }
-                                : 'toDart')
-                      ]).code,
-                    _ => refer('_')
-                        .asA(jsTypeAlt.emit(options?.toTypeOptions()))
-                        .code
-                  };
+            ..body = body.code;
         });
       })));
   }

web_generator/lib/src/interop_gen/transform/transformer.dart

@@ -1113,6 +1113,42 @@ class Transformer {
 
         return _getTypeFromTypeNode(refType,
             typeArg: typeArg, isNullable: isNullable ?? false);
+      case TSSyntaxKind.TypePredicate:
+        // in the future, we can be smarter about this
+        // but for now, we just have this as a boolean
+        return BuiltinType.primitiveType(PrimitiveType.boolean,
+            isNullable: isNullable);
+      case TSSyntaxKind.ConditionalType:
+        final conditionalType = type as TSConditionalTypeNode;
+        final trueType = _transformType(conditionalType.trueType);
+        final falseType = _transformType(conditionalType.falseType);
+
+        final types = [trueType, falseType]
+            .sorted((a, b) => a.id.toString().compareTo(b.id.toString()));
+
+        final expectedID = ID(type: 'type', name: types.join('|'));
+
+        if (typeMap.containsKey(expectedID.toString())) {
+          return (typeMap[expectedID.toString()] as UnionType)
+            ..isNullable = (isNullable ?? false);
+        }
+
+        final trueTypeName = trueType is NamedType
+            ? trueType.name
+            : trueType.dartName ?? trueType.id.name;
+
+        final falseTypeName = falseType is NamedType
+            ? falseType.name
+            : falseType.dartName ?? falseType.id.name;
+        final conditionalName = '${trueTypeName}Or$falseTypeName';
+
+        final un = UnionType(types: types, name: conditionalName);
+        final unType = typeMap.putIfAbsent(expectedID.toString(), () {
+          namer.markUsed(conditionalName);
+          return un;
+        });
+
+        return unType..isNullable = (isNullable ?? false);
       case TSSyntaxKind.TypeLiteral:
         // type literal
         final typeLiteralNode = type as TSTypeLiteralNode;

web_generator/lib/src/js/typescript.types.dart

@@ -100,6 +100,8 @@ extension type const TSSyntaxKind._(num _) {
   static const TSSyntaxKind FunctionType = TSSyntaxKind._(184);
   static const TSSyntaxKind ConstructorType = TSSyntaxKind._(185);
   static const TSSyntaxKind TypeOperator = TSSyntaxKind._(198);
+  static const TSSyntaxKind TypePredicate = TSSyntaxKind._(182);
+  static const TSSyntaxKind ConditionalType = TSSyntaxKind._(194);
 
   // Other
   static const TSSyntaxKind Identifier = TSSyntaxKind._(80);
@@ -202,6 +204,24 @@ extension type TSParenthesizedTypeNode._(JSObject _) implements TSTypeNode {
   external TSTypeNode get type;
 }
 
+@JS('TypePredicateNode')
+extension type TSTypePredicateNode._(JSObject _) implements TSTypeNode {
+  @redeclare
+  TSSyntaxKind get kind => TSSyntaxKind.TypePredicate;
+  external TSIdentifier get parameterName;
+  external TSTypeNode? get type;
+}
+
+@JS('ConditionalTypeNode')
+extension type TSConditionalTypeNode._(JSObject _) implements TSTypeNode {
+  @redeclare
+  TSSyntaxKind get kind => TSSyntaxKind.ConditionalType;
+  external TSTypeNode get checkType;
+  external TSTypeNode get extendsType;
+  external TSTypeNode get trueType;
+  external TSTypeNode get falseType;
+}
+
 @JS('TupleTypeNode')
 extension type TSTupleTypeNode._(JSObject _) implements TSTypeNode {
   external TSNodeArray<TSTypeNode> get elements;

web_generator/test/integration/interop_gen/ts_typing_expected.dart

@@ -15,6 +15,15 @@ external String myFunction(String param);
 @_i1.JS()
 external String myEnclosingFunction(_i1.JSFunction func);
 @_i1.JS()
+external bool objectIsProduct(_i1.JSObject obj);
+@_i1.JS()
+external AnonymousType_2194029 get randomNonTypedProduct;
+@_i1.JS()
+external ProductOrrandomNonTypedProduct objectAsProduct(
+  _i1.JSObject obj,
+  bool structured,
+);
+@_i1.JS()
 external _i1.JSArray<AnonymousType_9143117<T>>
     indexedArray<T extends _i1.JSAny?>(_i1.JSArray<T> arr);
 @_i1.JS()
@@ -84,8 +93,6 @@ external _i2.JSTuple4<_i1.JSString, _i1.JSNumber, _i1.JSBoolean, _i1.JSSymbol>
 @_i1.JS()
 external AnonymousUnion_7503220 get eightOrSixteen;
 @_i1.JS()
-external AnonymousType_2194029 get randomNonTypedProduct;
-@_i1.JS()
 external AnonymousType_1358595 get config;
 extension type MyProduct._(_i1.JSObject _) implements Product {
   external MyProduct(
@@ -125,6 +132,26 @@ external _i1.JSAny? get someIntersection;
 external AnonymousIntersection_4895242 get myThirdIntersection;
 @_i1.JS()
 external AnonymousIntersection_1711585 get myTypeGymnastic;
+extension type AnonymousType_2194029._(_i1.JSObject _) implements _i1.JSObject {
+  external AnonymousType_2194029({
+    double id,
+    String name,
+    double price,
+  });
+
+  external double id;
+
+  external String name;
+
+  external double price;
+}
+typedef Product = AnonymousType_2194029;
+extension type ProductOrrandomNonTypedProduct._(AnonymousType_2194029 _)
+    implements AnonymousType_2194029 {
+  Product get asProduct => _;
+
+  AnonymousType_2194029 get asRandomNonTypedProduct => _;
+}
 extension type AnonymousType_9143117<T extends _i1.JSAny?>._(_i1.JSObject _)
     implements _i1.JSObject {
   external AnonymousType_9143117({
@@ -210,19 +237,6 @@ extension type AnonymousUnion_7503220._(_i1.JSTypedArray _)
 
   _i1.JSUint16Array get asJSUint16Array => (_ as _i1.JSUint16Array);
 }
-extension type AnonymousType_2194029._(_i1.JSObject _) implements _i1.JSObject {
-  external AnonymousType_2194029({
-    double id,
-    String name,
-    double price,
-  });
-
-  external double id;
-
-  external String name;
-
-  external double price;
-}
 extension type AnonymousType_1358595._(_i1.JSObject _) implements _i1.JSObject {
   external AnonymousType_1358595({
     double discountRate,
@@ -233,7 +247,6 @@ extension type AnonymousType_1358595._(_i1.JSObject _) implements _i1.JSObject {
 
   external double taxRate;
 }
-typedef Product = AnonymousType_2194029;
 extension type AnonymousType_2773310._(_i1.JSObject _) implements _i1.JSObject {
   external AnonymousType_2773310({
     String id,

web_generator/test/integration/interop_gen/ts_typing_input.d.ts

@@ -29,7 +29,6 @@ export declare const myEnumValue2: typeof MyEnum;
 export declare function myFunction(param: string): string;
 export declare let myFunctionAlias: typeof myFunction;
 export declare let myFunctionAlias2: typeof myFunctionAlias;
-// export declare let myPreClone: typeof myComposedType;
 export declare function myEnclosingFunction(func: typeof myFunction): string;
 export declare const myEnclosingFunctionAlias: typeof myEnclosingFunction;
 export declare const myComposedType: ComposedType;
@@ -65,7 +64,9 @@ export declare class MyProduct implements Product {
     price: number;
     constructor(id: number, name: string, price: number);
 }
-export function indexedArray<T>(arr: T[]): { id: number, value: T }[];
+export declare function objectIsProduct(obj: object): obj is Product;
+export declare function objectAsProduct(obj: object, structured: boolean): (typeof structured) extends true ? Product : typeof randomNonTypedProduct;
+export declare function indexedArray<T>(arr: T[]): { id: number, value: T }[];
 export const responseObject: {
     id: string;
     value: any;