Add support for @groupDescription and @categoryDescription

Resolves #2494.

CHANGELOG.md

@@ -6,6 +6,10 @@
 -   Added support for the `@class` tag. When added to a comment on a variable or function, TypeDoc will convert the member as a class, #2479.
     Note: This should only be used on symbols which actually represent a class, but are not declared as a class for some reason.
 
+## Features
+
+-   Added support for `@groupDescription` and `@categoryDescription` to provide a description of groups and categories, #2494.
+
 ## Bug Fixes
 
 -   Fixed an issue where a namespace would not be created for merged function-namespaces which are declared as variables, #2478.

example/src/classes/CancellablePromise.ts

@@ -42,6 +42,12 @@ function isPromiseWithCancel<T>(value: unknown): value is PromiseWithCancel<T> {
  * [real-cancellable-promise](https://github.com/srmagura/real-cancellable-promise).
  *
  * @typeParam T what the `CancellablePromise` resolves to
+ *
+ * @groupDescription Methods
+ * Descriptions can be added for groups with `@groupDescription`, which will show up in
+ * the index where groups are listed. This works for both manually created groups which
+ * are created with `@group`, and implicit groups like the `Methods` group that this
+ * description is attached to.
  */
 export class CancellablePromise<T> {
     /**

example/src/index.ts

@@ -1,3 +1,9 @@
+/**
+ * @packageDocumentation
+ * @categoryDescription Component
+ * React Components -- This description is added with the `@categoryDescription` tag
+ * on the entry point in src/index.ts
+ */
 export * from "./functions";
 export * from "./variables";
 export * from "./types";

src/index.ts

@@ -4,6 +4,13 @@ export { EventDispatcher, Event } from "./lib/utils/events";
 export { resetReflectionID } from "./lib/models/reflections/abstract";
 /**
  * All symbols documented under the Models namespace are also available in the root import.
+ *
+ * @categoryDescription Types
+ * Describes a TypeScript type.
+ *
+ * @categoryDescription Reflections
+ * Describes a documentation entry. The root entry is a {@link ProjectReflection}
+ * and contains {@link DeclarationReflection} instances.
  */
 export * as Models from "./lib/models";
 /**

src/lib/converter/plugins/CategoryPlugin.ts

@@ -7,7 +7,7 @@ import { ReflectionCategory } from "../../models";
 import { Component, ConverterComponent } from "../components";
 import { Converter } from "../converter";
 import type { Context } from "../context";
-import { Option, getSortFunction } from "../../utils";
+import { Option, getSortFunction, removeIf } from "../../utils";
 
 /**
  * A handler that sorts and categorizes the found reflections in the resolving phase.
@@ -113,7 +113,10 @@ export class CategoryPlugin extends ConverterComponent {
         obj.groups.forEach((group) => {
             if (group.categories) return;
 
-            group.categories = this.getReflectionCategories(group.children);
+            group.categories = this.getReflectionCategories(
+                obj,
+                group.children,
+            );
             if (group.categories && group.categories.length > 1) {
                 group.categories.sort(CategoryPlugin.sortCatCallback);
             } else if (
@@ -130,7 +133,7 @@ export class CategoryPlugin extends ConverterComponent {
         if (!obj.children || obj.children.length === 0 || obj.categories) {
             return;
         }
-        obj.categories = this.getReflectionCategories(obj.children);
+        obj.categories = this.getReflectionCategories(obj, obj.children);
         if (obj.categories && obj.categories.length > 1) {
             obj.categories.sort(CategoryPlugin.sortCatCallback);
         } else if (
@@ -151,6 +154,7 @@ export class CategoryPlugin extends ConverterComponent {
      * @returns An array containing all children of the given reflection categorized
      */
     private getReflectionCategories(
+        parent: ContainerReflection,
         reflections: DeclarationReflection[],
     ): ReflectionCategory[] {
         const categories = new Map<string, ReflectionCategory>();
@@ -174,6 +178,27 @@ export class CategoryPlugin extends ConverterComponent {
             }
         }
 
+        if (parent.comment) {
+            removeIf(parent.comment.blockTags, (tag) => {
+                if (tag.tag === "@categoryDescription") {
+                    const { header, body } = Comment.splitPartsToHeaderAndBody(
+                        tag.content,
+                    );
+                    const cat = categories.get(header);
+                    if (cat) {
+                        cat.description = body;
+                    } else {
+                        this.application.logger.warn(
+                            `Comment for ${parent.getFriendlyFullName()} includes @categoryDescription for "${header}", but no child is placed in that category.`,
+                        );
+                    }
+
+                    return true;
+                }
+                return false;
+            });
+        }
+
         for (const cat of categories.values()) {
             this.sortFunction(cat.children);
         }

src/lib/converter/plugins/GroupPlugin.ts

@@ -101,7 +101,10 @@ export class GroupPlugin extends ConverterComponent {
             ) {
                 this.sortFunction(reflection.children);
             }
-            reflection.groups = this.getReflectionGroups(reflection.children);
+            reflection.groups = this.getReflectionGroups(
+                reflection,
+                reflection.children,
+            );
         }
     }
 
@@ -162,6 +165,7 @@ export class GroupPlugin extends ConverterComponent {
      * @returns An array containing all children of the given reflection grouped by their kind.
      */
     getReflectionGroups(
+        parent: ContainerReflection,
         reflections: DeclarationReflection[],
     ): ReflectionGroup[] {
         const groups = new Map<string, ReflectionGroup>();
@@ -178,6 +182,27 @@ export class GroupPlugin extends ConverterComponent {
             }
         });
 
+        if (parent.comment) {
+            removeIf(parent.comment.blockTags, (tag) => {
+                if (tag.tag === "@groupDescription") {
+                    const { header, body } = Comment.splitPartsToHeaderAndBody(
+                        tag.content,
+                    );
+                    const cat = groups.get(header);
+                    if (cat) {
+                        cat.description = body;
+                    } else {
+                        this.application.logger.warn(
+                            `Comment for ${parent.getFriendlyFullName()} includes @groupDescription for "${header}", but no child is placed in that group.`,
+                        );
+                    }
+
+                    return true;
+                }
+                return false;
+            });
+        }
+
         return Array.from(groups.values()).sort(GroupPlugin.sortGroupCallback);
     }
 

src/lib/converter/plugins/LinkResolverPlugin.ts

@@ -2,7 +2,13 @@ import { Component, ConverterComponent } from "../components";
 import type { Context, ExternalResolveResult } from "../../converter";
 import { ConverterEvents } from "../converter-events";
 import { Option, ValidationOptions } from "../../utils";
-import { DeclarationReflection, ProjectReflection } from "../../models";
+import {
+    ContainerReflection,
+    DeclarationReflection,
+    ProjectReflection,
+    Reflection,
+    ReflectionCategory,
+} from "../../models";
 import { discoverAllReferenceTypes } from "../../utils/reflections";
 import { ApplicationEvents } from "../../application-events";
 
@@ -45,6 +51,31 @@ export class LinkResolverPlugin extends ConverterComponent {
                     reflection,
                 );
             }
+
+            if (reflection instanceof ContainerReflection) {
+                if (reflection.groups) {
+                    for (const group of reflection.groups) {
+                        if (group.description) {
+                            group.description = this.owner.resolveLinks(
+                                group.description,
+                                reflection,
+                            );
+                        }
+
+                        if (group.categories) {
+                            for (const cat of group.categories) {
+                                this.resolveCategoryLinks(cat, reflection);
+                            }
+                        }
+                    }
+                }
+
+                if (reflection.categories) {
+                    for (const cat of reflection.categories) {
+                        this.resolveCategoryLinks(cat, reflection);
+                    }
+                }
+            }
         }
 
         if (project.readme) {
@@ -75,4 +106,16 @@ export class LinkResolverPlugin extends ConverterComponent {
             }
         }
     }
+
+    private resolveCategoryLinks(
+        category: ReflectionCategory,
+        owner: Reflection,
+    ) {
+        if (category.description) {
+            category.description = this.owner.resolveLinks(
+                category.description,
+                owner,
+            );
+        }
+    }
 }

src/lib/models/ReflectionCategory.ts

@@ -1,4 +1,8 @@
-import type { DeclarationReflection } from ".";
+import {
+    Comment,
+    type CommentDisplayPart,
+    type DeclarationReflection,
+} from ".";
 import type { Serializer, JSONOutput, Deserializer } from "../serialization";
 
 /**
@@ -14,6 +18,11 @@ export class ReflectionCategory {
      */
     title: string;
 
+    /**
+     * The user specified description, if any, set with `@categoryDescription`
+     */
+    description?: CommentDisplayPart[];
+
     /**
      * All reflections of this category.
      */
@@ -35,9 +44,12 @@ export class ReflectionCategory {
         return this.children.every((child) => child.hasOwnDocument);
     }
 
-    toObject(_serializer: Serializer): JSONOutput.ReflectionCategory {
+    toObject(serializer: Serializer): JSONOutput.ReflectionCategory {
         return {
             title: this.title,
+            description: this.description
+                ? Comment.serializeDisplayParts(serializer, this.description)
+                : undefined,
             children:
                 this.children.length > 0
                     ? this.children.map((child) => child.id)
@@ -46,6 +58,13 @@ export class ReflectionCategory {
     }
 
     fromObject(de: Deserializer, obj: JSONOutput.ReflectionCategory) {
+        if (obj.description) {
+            this.description = Comment.deserializeDisplayParts(
+                de,
+                obj.description,
+            );
+        }
+
         if (obj.children) {
             de.defer((project) => {
                 for (const childId of obj.children || []) {

src/lib/models/ReflectionGroup.ts

@@ -1,5 +1,10 @@
 import { ReflectionCategory } from "./ReflectionCategory";
-import type { DeclarationReflection, Reflection } from ".";
+import {
+    Comment,
+    type CommentDisplayPart,
+    type DeclarationReflection,
+    type Reflection,
+} from ".";
 import type { Serializer, JSONOutput, Deserializer } from "../serialization";
 
 /**
@@ -15,6 +20,11 @@ export class ReflectionGroup {
      */
     title: string;
 
+    /**
+     * User specified description via `@groupDescription`, if specified.
+     */
+    description?: CommentDisplayPart[];
+
     /**
      * All reflections of this group.
      */
@@ -48,6 +58,9 @@ export class ReflectionGroup {
     toObject(serializer: Serializer): JSONOutput.ReflectionGroup {
         return {
             title: this.title,
+            description: this.description
+                ? Comment.serializeDisplayParts(serializer, this.description)
+                : undefined,
             children:
                 this.children.length > 0
                     ? this.children.map((child) => child.id)
@@ -57,6 +70,13 @@ export class ReflectionGroup {
     }
 
     fromObject(de: Deserializer, obj: JSONOutput.ReflectionGroup) {
+        if (obj.description) {
+            this.description = Comment.deserializeDisplayParts(
+                de,
+                obj.description,
+            );
+        }
+
         if (obj.categories) {
             this.categories = obj.categories.map((catObj) => {
                 const cat = new ReflectionCategory(catObj.title);

src/lib/models/comments/comment.ts

@@ -194,7 +194,7 @@ export class Comment {
     /**
      * Helper utility to clone {@link Comment.summary} or {@link CommentTag.content}
      */
-    static cloneDisplayParts(parts: CommentDisplayPart[]) {
+    static cloneDisplayParts(parts: readonly CommentDisplayPart[]) {
         return parts.map((p) => ({ ...p }));
     }
 
@@ -304,6 +304,61 @@ export class Comment {
         return result;
     }
 
+    /**
+     * Splits the provided parts into a header (first line, as a string)
+     * and body (remaining lines). If the header line contains inline tags
+     * they will be serialized to a string.
+     */
+    static splitPartsToHeaderAndBody(parts: readonly CommentDisplayPart[]): {
+        header: string;
+        body: CommentDisplayPart[];
+    } {
+        let index = parts.findIndex((part): boolean => {
+            switch (part.kind) {
+                case "text":
+                case "code":
+                    return part.text.includes("\n");
+                case "inline-tag":
+                    return false;
+            }
+        });
+
+        if (index === -1) {
+            return {
+                header: Comment.combineDisplayParts(parts),
+                body: [],
+            };
+        }
+
+        // Do not split a code block, stop the header at the end of the previous block
+        if (parts[index].kind === "code") {
+            --index;
+        }
+
+        if (index === -1) {
+            return { header: "", body: Comment.cloneDisplayParts(parts) };
+        }
+
+        let header = Comment.combineDisplayParts(parts.slice(0, index));
+        const split = parts[index].text.indexOf("\n");
+
+        let body: CommentDisplayPart[];
+        if (split === -1) {
+            header += parts[index].text;
+            body = Comment.cloneDisplayParts(parts.slice(index + 1));
+        } else {
+            header += parts[index].text.substring(0, split);
+            body = Comment.cloneDisplayParts(parts.slice(index));
+            body[0].text = body[0].text.substring(split + 1);
+        }
+
+        if (!body[0].text) {
+            body.shift();
+        }
+
+        return { header: header.trim(), body };
+    }
+
     /**
      * The content of the comment which is not associated with a block tag.
      */