refactored mutator to listen for returned data from event listeners

app/src/data/entities/Entity.ts

@@ -192,10 +192,26 @@ export class Entity<
       this.data = data;
    }
 
+   // @todo: add tests
    isValidData(data: EntityData, context: TActionContext, explain?: boolean): boolean {
+      if (typeof data !== "object") {
+         if (explain) {
+            throw new Error(`Entity "${this.name}" data must be an object`);
+         }
+      }
+
       const fields = this.getFillableFields(context, false);
-      //const fields = this.fields;
-      //console.log("data", data);
+      const field_names = fields.map((f) => f.name);
+      const given_keys = Object.keys(data);
+
+      if (given_keys.some((key) => !field_names.includes(key))) {
+         if (explain) {
+            throw new Error(
+               `Entity "${this.name}" data must only contain known keys, got: "${given_keys}"`
+            );
+         }
+      }
+
       for (const field of fields) {
          if (!field.isValid(data[field.name], context)) {
             console.log("Entity.isValidData:invalid", context, field.name, data[field.name]);

app/src/data/entities/Mutator.ts

@@ -132,14 +132,17 @@ export class Mutator<
          throw new Error(`Creation of system entity "${entity.name}" is disabled`);
       }
 
-      // @todo: establish the original order from "data"
+      const result = await this.emgr.emit(
+         new Mutator.Events.MutatorInsertBefore({ entity, data: data as any })
+      );
+
+      // if listener returned, take what's returned
+      const _data = result.returned ? result.params.data : data;
       const validatedData = {
          ...entity.getDefaultObject(),
-         ...(await this.getValidatedData(data, "create"))
+         ...(await this.getValidatedData(_data, "create"))
       };
 
-      await this.emgr.emit(new Mutator.Events.MutatorInsertBefore({ entity, data: validatedData }));
-
       // check if required fields are present
       const required = entity.getRequiredFields();
       for (const field of required) {
@@ -169,16 +172,17 @@ export class Mutator<
          throw new Error("ID must be provided for update");
       }
 
-      const validatedData = await this.getValidatedData(data, "update");
-
-      await this.emgr.emit(
+      const result = await this.emgr.emit(
          new Mutator.Events.MutatorUpdateBefore({
             entity,
             entityId: id,
-            data: validatedData as any
+            data
          })
       );
 
+      const _data = result.returned ? result.params.data : data;
+      const validatedData = await this.getValidatedData(_data, "update");
+
       const query = this.conn
          .updateTable(entity.name)
          .set(validatedData as any)

app/src/data/events/index.ts

@@ -1,20 +1,48 @@
 import type { PrimaryFieldType } from "core";
-import { Event } from "core/events";
+import { Event, InvalidEventReturn } from "core/events";
 import type { Entity, EntityData } from "../entities";
 import type { RepoQuery } from "../server/data-query-impl";
 
-export class MutatorInsertBefore extends Event<{ entity: Entity; data: EntityData }> {
+export class MutatorInsertBefore extends Event<{ entity: Entity; data: EntityData }, EntityData> {
    static override slug = "mutator-insert-before";
+
+   override validate(data: EntityData) {
+      const { entity } = this.params;
+      if (!entity.isValidData(data, "create")) {
+         throw new InvalidEventReturn("EntityData", "invalid");
+      }
+
+      return this.clone({
+         entity,
+         data
+      });
+   }
 }
 export class MutatorInsertAfter extends Event<{ entity: Entity; data: EntityData }> {
    static override slug = "mutator-insert-after";
 }
-export class MutatorUpdateBefore extends Event<{
-   entity: Entity;
-   entityId: PrimaryFieldType;
-   data: EntityData;
-}> {
+export class MutatorUpdateBefore extends Event<
+   {
+      entity: Entity;
+      entityId: PrimaryFieldType;
+      data: EntityData;
+   },
+   EntityData
+> {
    static override slug = "mutator-update-before";
+
+   override validate(data: EntityData) {
+      const { entity, ...rest } = this.params;
+      if (!entity.isValidData(data, "update")) {
+         throw new InvalidEventReturn("EntityData", "invalid");
+      }
+
+      return this.clone({
+         ...rest,
+         entity,
+         data
+      });
+   }
 }
 export class MutatorUpdateAfter extends Event<{
    entity: Entity;