fix(compiler-cli): correct extraction of generics from type aliases (#58548)

alan-agius4 · thePunderWoman · commit 4c3816085363 · 2024-11-08T17:15:08.000Z
**Before:** ```ts type HttpEvent = | HttpSentEvent | HttpHeaderResponse | HttpResponse<T> | HttpProgressEvent | HttpUserEvent<T> ``` **After:** ```ts type HttpEvent<T> = | HttpSentEvent | HttpHeaderResponse | HttpResponse<T> | HttpProgressEvent | HttpUserEvent<T> ``` PR Close #58548
diff --git a/adev/shared-docs/pipeline/api-gen/rendering/entities.ts b/adev/shared-docs/pipeline/api-gen/rendering/entities.ts
@@ -94,7 +94,9 @@ export interface ConstantEntry extends DocEntry {
 }
 
 /** Documentation entity for a type alias. */
-export type TypeAliasEntry = ConstantEntry;
+export interface TypeAliasEntry extends ConstantEntry {
+  generics: GenericEntry[];
+}
 
 /** Documentation entity for a TypeScript class. */
 export interface ClassEntry extends DocEntry {
diff --git a/adev/shared-docs/pipeline/api-gen/rendering/transforms/code-transforms.ts b/adev/shared-docs/pipeline/api-gen/rendering/transforms/code-transforms.ts
@@ -243,7 +243,8 @@ export function mapDocEntryToCode(entry: DocEntry): CodeTableOfContentsData {
   }
 
   if (isTypeAliasEntry(entry)) {
-    const contents = `type ${entry.name} = ${entry.type}`;
+    const generics = makeGenericsText(entry.generics);
+    const contents = `type ${entry.name}${generics} = ${entry.type}`;
 
     if (isDeprecated) {
       const numberOfLinesOfCode = getNumberOfLinesOfCode(contents);
@@ -446,7 +447,6 @@ function appendPrefixAndSuffix(entry: DocEntry, codeTocData: CodeTableOfContents
 
   if (isClassEntry(entry) || isInterfaceEntry(entry)) {
     const generics = makeGenericsText(entry.generics);
-
     const extendsStr = entry.extends ? ` extends ${entry.extends}` : '';
     // TODO: remove the ? when we distinguish Class & Decorator entries
     const implementsStr =
diff --git a/packages/compiler-cli/src/ngtsc/docs/src/entities.ts b/packages/compiler-cli/src/ngtsc/docs/src/entities.ts
@@ -100,14 +100,16 @@ export interface ConstantEntry extends DocEntry {
 }
 
 /** Documentation entity for a type alias. */
-export type TypeAliasEntry = ConstantEntry;
+export interface TypeAliasEntry extends ConstantEntry {
+  generics: GenericEntry[];
+}
 
 /** Documentation entity for a TypeScript class. */
 export interface ClassEntry extends DocEntry {
   isAbstract: boolean;
   members: MemberEntry[];
-  generics: GenericEntry[];
   extends?: string;
+  generics: GenericEntry[];
   implements: string[];
 }
 
diff --git a/packages/compiler-cli/src/ngtsc/docs/src/type_alias_extractor.ts b/packages/compiler-cli/src/ngtsc/docs/src/type_alias_extractor.ts
@@ -9,6 +9,7 @@ import ts from 'typescript';
 
 import {EntryType} from './entities';
 import {extractJsDocDescription, extractJsDocTags, extractRawJsDoc} from './jsdoc_extractor';
+import {extractGenerics} from './generics_extractor';
 
 /** Extract the documentation entry for a type alias. */
 export function extractTypeAlias(declaration: ts.TypeAliasDeclaration) {
@@ -20,6 +21,7 @@ export function extractTypeAlias(declaration: ts.TypeAliasDeclaration) {
     name: declaration.name.getText(),
     type: declaration.type.getText(),
     entryType: EntryType.TypeAlias,
+    generics: extractGenerics(declaration),
     rawComment: extractRawJsDoc(declaration),
     description: extractJsDocDescription(declaration),
     jsdocTags: extractJsDocTags(declaration),
diff --git a/packages/compiler-cli/test/ngtsc/doc_extraction/type_alias_doc_extraction_spec.ts b/packages/compiler-cli/test/ngtsc/doc_extraction/type_alias_doc_extraction_spec.ts
@@ -63,5 +63,26 @@ runInEachFileSystem(() => {
           age: number;
         }`);
     });
+
+    it('should extract type aliases based with generics', () => {
+      env.write(
+        'index.ts',
+        `
+          type Foo<T> = undefined;
+          export type Bar<T extends string> = Foo<T>;
+        `,
+      );
+
+      const docs: DocEntry[] = env.driveDocsExtraction('index.ts');
+      expect(docs.length).toBe(1);
+
+      const typeAliasEntry = docs[0] as TypeAliasEntry;
+      expect(typeAliasEntry.name).toBe('Bar');
+      expect(typeAliasEntry.entryType).toBe(EntryType.TypeAlias);
+      expect(typeAliasEntry.type).toBe('Foo<T>');
+      expect(typeAliasEntry.generics).toEqual([
+        {name: 'T', constraint: 'string', default: undefined},
+      ]);
+    });
   });
 });

Original file line number	Diff line number	Diff line change
`@@ -94,7 +94,9 @@ export interface ConstantEntry extends DocEntry {`
`94`	`94`	`}`
`95`	`95`
`96`	`96`	`/** Documentation entity for a type alias. */`
`97`		`-export type TypeAliasEntry = ConstantEntry;`
	`97`	`+export interface TypeAliasEntry extends ConstantEntry {`
	`98`	`+ generics: GenericEntry[];`
	`99`	`+}`
`98`	`100`
`99`	`101`	`/** Documentation entity for a TypeScript class. */`
`100`	`102`	`export interface ClassEntry extends DocEntry {`