refactored mutator to listen for returned data from event listeners

app/src/core/config.ts

@@ -5,8 +5,13 @@ import type { Generated } from "kysely";
 
 export type PrimaryFieldType = number | Generated<number>;
 
-// biome-ignore lint/suspicious/noEmptyInterface: <explanation>
-export interface DB {}
+export interface DB {
+   // make sure to make unknown as "any"
+   [key: string]: {
+      id: PrimaryFieldType;
+      [key: string]: any;
+   };
+}
 
 export const config = {
    server: {

app/src/core/events/Event.ts

@@ -1,3 +1,8 @@
+export type EventClass = {
+   new (params: any): Event<any, any>;
+   slug: string;
+};
+
 export abstract class Event<Params = any, Returning = void> {
    _returning!: Returning;
 
@@ -9,7 +14,9 @@ export abstract class Event<Params = any, Returning = void> {
    params: Params;
    returned: boolean = false;
 
-   validate(value: Returning): Event<Params, Returning> | void {}
+   validate(value: Returning): Event<Params, Returning> | void {
+      throw new EventReturnedWithoutValidation(this as any, value);
+   }
 
    protected clone<This extends Event<Params, Returning> = Event<Params, Returning>>(
       this: This,
@@ -39,3 +46,13 @@ export class InvalidEventReturn extends Error {
       super(`Expected "${expected}", got "${given}"`);
    }
 }
+
+export class EventReturnedWithoutValidation extends Error {
+   constructor(
+      event: EventClass,
+      public data: any
+   ) {
+      // @ts-expect-error slug is static
+      super(`Event "${event.constructor.slug}" returned without validation`);
+   }
+}

app/src/core/events/EventManager.ts

@@ -1,4 +1,4 @@
-import { type Event, InvalidEventReturn } from "./Event";
+import { type Event, type EventClass, InvalidEventReturn } from "./Event";
 import { EventListener, type ListenerHandler, type ListenerMode } from "./EventListener";
 
 export type RegisterListenerConfig =
@@ -12,10 +12,8 @@ export interface EmitsEvents {
    emgr: EventManager;
 }
 
-export type EventClass = {
-   new (params: any): Event<any, any>;
-   slug: string;
-};
+// for compatibility, moved it to Event.ts
+export type { EventClass };
 
 export class EventManager<
    RegisteredEvents extends Record<string, EventClass> = Record<string, EventClass>