Migrate Some Type Literals to Interfaces

src/ts/class.ts

@@ -17,11 +17,10 @@ import {
   factory,
   DeclarationStatement,
   ModifierFlags,
-  NodeFlags,
   Statement,
-  TypeAliasDeclaration,
   TypeNode,
-  VariableStatement,
+  SyntaxKind,
+  InterfaceDeclaration,
 } from 'typescript';
 
 import {Log} from '../logging';
@@ -219,66 +218,53 @@ export class Class {
     return this.namedParents().length === 1 && this._props.size === 0;
   }
 
-  private baseNode(
+  private baseDecl(
     skipDeprecatedProperties: boolean,
     context: Context
-  ): TypeNode | undefined {
+  ): InterfaceDeclaration | undefined {
     if (this.skipBase()) {
       return undefined;
     }
 
+    const baseName = this.baseName();
+    assert(baseName, 'If a baseNode is defined, baseName must be defined.');
+
     const parentTypes = this.namedParents().map(p =>
-      factory.createTypeReferenceNode(p, [])
+      factory.createExpressionWithTypeArguments(factory.createIdentifier(p), [])
     );
-    const parentNode =
+
+    const heritage = factory.createHeritageClause(
+      SyntaxKind.ExtendsKeyword,
       parentTypes.length === 0
-        ? factory.createTypeReferenceNode('Partial', [
-            factory.createTypeReferenceNode(
-              IdReferenceName,
-              /*typeArguments=*/ []
+        ? [
+            factory.createExpressionWithTypeArguments(
+              factory.createIdentifier('Partial'),
+              /*typeArguments=*/ [
+                factory.createTypeReferenceNode(
+                  IdReferenceName,
+                  /*typeArguments=*/ []
+                ),
+              ]
             ),
-          ])
-        : parentTypes.length === 1
-        ? parentTypes[0]
-        : factory.createParenthesizedType(
-            factory.createIntersectionTypeNode(parentTypes)
-          );
-
-    // Properties part.
-    const propLiteral = factory.createTypeLiteralNode([
-      // ... then everything else.
-      ...this.properties()
-        .filter(property => !property.deprecated || !skipDeprecatedProperties)
-        .map(prop => prop.toNode(context)),
-    ]);
-
-    if (propLiteral.members.length > 0) {
-      return factory.createIntersectionTypeNode([parentNode, propLiteral]);
-    } else {
-      return parentNode;
-    }
-  }
-
-  private baseDecl(
-    skipDeprecatedProperties: boolean,
-    context: Context
-  ): TypeAliasDeclaration | undefined {
-    const baseNode = this.baseNode(skipDeprecatedProperties, context);
+          ]
+        : parentTypes
+    );
 
-    if (!baseNode) return undefined;
-    const baseName = this.baseName();
-    assert(baseName, 'If a baseNode is defined, baseName must be defined.');
+    const members = this.properties()
+      .filter(property => !property.deprecated || !skipDeprecatedProperties)
+      .map(prop => prop.toNode(context));
 
-    return factory.createTypeAliasDeclaration(
+    return factory.createInterfaceDeclaration(
       /*decorators=*/ [],
       /*modifiers=*/ [],
       baseName,
       /*typeParameters=*/ [],
-      baseNode
+      /*heritageClause=*/ [heritage],
+      /*members=*/ members
     );
   }
 
-  protected leafDecl(context: Context): TypeAliasDeclaration | undefined {
+  protected leafDecl(context: Context): InterfaceDeclaration | undefined {
     const leafName = this.leafName();
     if (!leafName) return undefined;
 
@@ -293,19 +279,20 @@ export class Class {
       /*typeArguments=*/ []
     );
 
-    const thisType = factory.createIntersectionTypeNode([
-      factory.createTypeLiteralNode([
-        new TypeProperty(this.subject).toNode(context),
-      ]),
-      baseTypeReference,
-    ]);
-
-    return factory.createTypeAliasDeclaration(
+    return factory.createInterfaceDeclaration(
       /*decorators=*/ [],
       /*modifiers=*/ [],
       leafName,
       /*typeParameters=*/ [],
-      thisType
+      /*heritage=*/ [
+        factory.createHeritageClause(SyntaxKind.ExtendsKeyword, [
+          factory.createExpressionWithTypeArguments(
+            factory.createIdentifier(baseName),
+            /*typeArguments=*/ []
+          ),
+        ]),
+      ],
+      /*members=*/ [new TypeProperty(this.subject).toNode(context)]
     );
   }
 

test/baselines/category_test.ts

@@ -57,18 +57,18 @@ test(`baseine_${basename(__filename)}`, async () => {
 
     export type Text = string;
 
-    type DistilleryLeaf = {
+    interface DistilleryLeaf extends ThingBase {
         \\"@type\\": \\"Distillery\\";
-    } & ThingBase;
+    }
     /** A distillery. */
     export type Distillery = DistilleryLeaf;
 
-    type ThingBase = Partial<IdReference> & {
+    interface ThingBase extends Partial<IdReference> {
         \\"name\\"?: SchemaValue<Text>;
-    };
-    type ThingLeaf = {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     export type Thing = ThingLeaf | Distillery;
 
     "

test/baselines/comments_test.ts

@@ -59,7 +59,7 @@ test(`baseine_${basename(__filename)}`, async () => {
     /** Data type: Text. */
     export type Text = string;
 
-    type ThingBase = Partial<IdReference> & {
+    interface ThingBase extends Partial<IdReference> {
         /**
          * Reminds me of this quote:
          * \`FooBar\`
@@ -69,10 +69,10 @@ test(`baseine_${basename(__filename)}`, async () => {
         \\"knows\\"?: SchemaValue<Text>;
         /** Names are great! {@link X Y} */
         \\"name\\"?: SchemaValue<Text>;
-    };
-    type ThingLeaf = {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     /**
      * Things are amazing!
      *

test/baselines/data_type_union_test.ts

@@ -64,13 +64,13 @@ test(`baseine_${basename(__filename)}`, async () => {
     /** The basic data types such as Integers, Strings, etc. */
     export type DataType = Number | Text;
 
-    type ThingBase = Partial<IdReference> & {
+    interface ThingBase extends Partial<IdReference> {
         \\"age\\"?: SchemaValue<Number>;
         \\"name\\"?: SchemaValue<Text>;
-    };
-    type ThingLeaf = {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     export type Thing = ThingLeaf;
 
     "

test/baselines/default_ontology_test.ts

@@ -44,10 +44,11 @@ test(`baseine_${basename(__filename)}`, async () => {
         \\"@id\\": string;
     };
 
-    type ThingBase = Partial<IdReference>;
-    type ThingLeaf = {
+    interface ThingBase extends Partial<IdReference> {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     export type Thing = ThingLeaf;
 
     "

test/baselines/deprecated_objects_test.ts

@@ -79,43 +79,43 @@ test(`baseine_${basename(__filename)}`, async () => {
 
     export type Text = string;
 
-    type CarBase = ThingBase & {
+    interface CarBase extends ThingBase {
         \\"doorNumber\\"?: SchemaValue<Number>;
-    };
-    type CarLeaf = {
+    }
+    interface CarLeaf extends CarBase {
         \\"@type\\": \\"Car\\";
-    } & CarBase;
+    }
     export type Car = CarLeaf;
 
-    type PersonLikeBase = ThingBase & {
+    interface PersonLikeBase extends ThingBase {
         \\"height\\"?: SchemaValue<Number>;
-    };
-    type PersonLikeLeaf = {
+    }
+    interface PersonLikeLeaf extends PersonLikeBase {
         \\"@type\\": \\"PersonLike\\";
-    } & PersonLikeBase;
+    }
     export type PersonLike = PersonLikeLeaf;
 
-    type ThingBase = Partial<IdReference> & {
+    interface ThingBase extends Partial<IdReference> {
         \\"name\\"?: SchemaValue<Text>;
         /**
          * Names are great! {@link X Y}
          * @deprecated Consider using http://schema.org/name or http://schema.org/height instead.
          */
         \\"names\\"?: SchemaValue<Text>;
-    };
-    type ThingLeaf = {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     export type Thing = ThingLeaf | Car | PersonLike | Vehicle;
 
-    type VehicleBase = ThingBase & {
+    interface VehicleBase extends ThingBase {
         \\"doorNumber\\"?: SchemaValue<Number>;
         /** @deprecated Consider using http://schema.org/doorNumber instead. */
         \\"doors\\"?: SchemaValue<Number>;
-    };
-    type VehicleLeaf = {
+    }
+    interface VehicleLeaf extends VehicleBase {
         \\"@type\\": \\"Vehicle\\";
-    } & VehicleBase;
+    }
     /** @deprecated Use Car instead. */
     export type Vehicle = VehicleLeaf;
 

test/baselines/duplicate_comments_test.ts

@@ -59,13 +59,13 @@ test(`baseine_${basename(__filename)}`, async () => {
 
     export type Text = string;
 
-    type ThingBase = Partial<IdReference> & {
+    interface ThingBase extends Partial<IdReference> {
         /** Names are great! {@link X Y} */
         \\"name\\"?: SchemaValue<Text>;
-    };
-    type ThingLeaf = {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     /**
      * Things are amazing!
      *

test/baselines/enum_skipped_test.ts

@@ -53,10 +53,11 @@ test(`baseine_${basename(__filename)}`, async () => {
         \\"@id\\": string;
     };
 
-    type ThingBase = Partial<IdReference>;
-    type ThingLeaf = {
+    interface ThingBase extends Partial<IdReference> {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     /** A Thing! */
     export type Thing = \\"http://schema.org/a\\" | \\"https://schema.org/a\\" | \\"a\\" | \\"http://schema.org/b\\" | \\"https://schema.org/b\\" | \\"b\\" | \\"http://schema.org/c\\" | \\"https://schema.org/c\\" | \\"c\\" | \\"http://schema.org/d\\" | \\"https://schema.org/d\\" | \\"d\\" | \\"https://schema.org/e\\" | \\"e\\" | \\"http://google.com/f\\" | \\"https://google.com/f\\" | ThingLeaf;
 

test/baselines/inheritance_multiple_test.ts

@@ -65,28 +65,28 @@ test(`baseine_${basename(__filename)}`, async () => {
 
     export type Text = string;
 
-    type PersonLikeBase = ThingBase & {
+    interface PersonLikeBase extends ThingBase {
         \\"height\\"?: SchemaValue<Number>;
-    };
-    type PersonLikeLeaf = {
+    }
+    interface PersonLikeLeaf extends PersonLikeBase {
         \\"@type\\": \\"PersonLike\\";
-    } & PersonLikeBase;
+    }
     export type PersonLike = PersonLikeLeaf;
 
-    type ThingBase = Partial<IdReference> & {
+    interface ThingBase extends Partial<IdReference> {
         \\"name\\"?: SchemaValue<Text>;
-    };
-    type ThingLeaf = {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     export type Thing = ThingLeaf | PersonLike | Vehicle;
 
-    type VehicleBase = ThingBase & {
+    interface VehicleBase extends ThingBase {
         \\"doors\\"?: SchemaValue<Number>;
-    };
-    type VehicleLeaf = {
+    }
+    interface VehicleLeaf extends VehicleBase {
         \\"@type\\": \\"Vehicle\\";
-    } & VehicleBase;
+    }
     export type Vehicle = VehicleLeaf;
 
     "

test/baselines/inheritance_one_test.ts

@@ -60,20 +60,20 @@ test(`baseine_${basename(__filename)}`, async () => {
 
     export type Text = string;
 
-    type PersonLikeBase = ThingBase & {
+    interface PersonLikeBase extends ThingBase {
         \\"height\\"?: SchemaValue<Number>;
-    };
-    type PersonLikeLeaf = {
+    }
+    interface PersonLikeLeaf extends PersonLikeBase {
         \\"@type\\": \\"PersonLike\\";
-    } & PersonLikeBase;
+    }
     export type PersonLike = PersonLikeLeaf;
 
-    type ThingBase = Partial<IdReference> & {
+    interface ThingBase extends Partial<IdReference> {
         \\"name\\"?: SchemaValue<Text>;
-    };
-    type ThingLeaf = {
+    }
+    interface ThingLeaf extends ThingBase {
         \\"@type\\": \\"Thing\\";
-    } & ThingBase;
+    }
     export type Thing = ThingLeaf | PersonLike;
 
     "