feat: add validator run event to allow plugins to perform custom validation

Author: RebeccaStevens

src/lib/application-events.ts

@@ -1,3 +1,4 @@
 export const ApplicationEvents = {
     BOOTSTRAP_END: "bootstrapEnd",
-};
+    VALIDATION_RUN: "validationRun",
+} as const;

src/lib/application.ts

@@ -107,6 +107,12 @@ export class Application extends ChildableComponent<
      */
     static readonly EVENT_BOOTSTRAP_END = ApplicationEvents.BOOTSTRAP_END;
 
+    /**
+     * Emitted when validation is being run.
+     * The listener will be given an instance of {@link ProjectReflection}.
+     */
+    static readonly EVENT_VALIDATION_RUN = ApplicationEvents.VALIDATION_RUN;
+
     /**
      * Create a new TypeDoc application instance.
      */
@@ -431,6 +437,8 @@ export class Application extends ChildableComponent<
             validateLinks(project, this.logger);
         }
 
+        this.trigger(Application.EVENT_VALIDATION_RUN, project);
+
         this.logger.verbose(`Validation took ${Date.now() - start}ms`);
     }
 

src/lib/utils/events.ts

@@ -7,6 +7,9 @@
 // The Events object is a typesafe conversion of Backbones Events object:
 // https://github.com/jashkenas/backbone/blob/05fde9e201f7e2137796663081105cd6dad12a98/backbone.js#L119-L374
 
+import type { ProjectReflection } from "../models/index";
+import type { Application } from "../application";
+
 const uniqueId = (function () {
     const prefixes: Record<string, number | undefined> = Object.create(null);
     return function (prefix: string) {
@@ -433,6 +436,12 @@ export class EventDispatcher {
         context?: any,
         priority?: number
     ): this;
+    on(
+        name: (typeof Application)["EVENT_VALIDATION_RUN"],
+        callback: (project: ProjectReflection) => void,
+        context?: any,
+        priority?: number
+    ): this;
     on(
         name: string,
         callback: EventCallback,
@@ -441,7 +450,7 @@ export class EventDispatcher {
     ): this;
     on(
         nameOrMap: EventMap | string,
-        callback: EventCallback,
+        callback?: EventCallback,
         context?: any,
         priority?: number
     ) {