mm: added diff event + plugin to write down diffs

app/src/core/index.ts

@@ -39,6 +39,7 @@ export {
    type ParseOptions,
    InvalidSchemaError,
 } from "./object/schema";
+export * as $diff from "./object/diff";
 
 export * from "./drivers";
 export * from "./events";

app/src/modules/ModuleManager.ts

@@ -128,8 +128,16 @@ export class ModuleManagerConfigUpdateEvent<
 }> {
    static override slug = "mm-config-update";
 }
+
+export class ModuleManagerConfigDiffEvent extends ModuleManagerEvent<{
+   diffs: $diff.DiffEntry[];
+}> {
+   static override slug = "mm-config-diff";
+}
+
 export const ModuleManagerEvents = {
    ModuleManagerConfigUpdateEvent,
+   ModuleManagerConfigDiffEvent,
 };
 
 // @todo: cleanup old diffs on upgrade
@@ -349,6 +357,13 @@ export class ModuleManager {
                // validate diffs, it'll throw on invalid
                this.validateDiffs(diffs);
 
+               await this.emgr.emit(
+                  new ModuleManagerConfigDiffEvent({
+                     ctx: this.ctx(),
+                     diffs: $diff.clone(diffs),
+                  }),
+               );
+
                const date = new Date();
                // store diff
                await this.mutator().insertOne({

app/src/plugins/dev/sync-diffs.plugin.ts

@@ -0,0 +1,26 @@
+import { type App, ModuleManagerEvents, type AppPlugin } from "bknd";
+import type { $diff } from "bknd/core";
+
+export type SyncDiffsOptions = {
+   enabled?: boolean;
+   write: (name: string, diffs: $diff.DiffEntry[]) => Promise<void>;
+};
+
+export function syncDiffs({ enabled = true, write }: SyncDiffsOptions): AppPlugin {
+   return (app: App) => ({
+      name: "bknd-sync-diffs",
+      onBuilt: async () => {
+         if (!enabled) return;
+         app.emgr.onEvent(
+            ModuleManagerEvents.ModuleManagerConfigDiffEvent,
+            async (event) => {
+               const name = `${new Date().getTime()}.diff.json`;
+               await write?.(name, event.params.diffs);
+            },
+            {
+               id: "sync-config",
+            },
+         );
+      },
+   });
+}

app/src/plugins/index.ts

@@ -5,3 +5,4 @@ export {
 export { showRoutes, type ShowRoutesOptions } from "./dev/show-routes.plugin";
 export { syncConfig, type SyncConfigOptions } from "./dev/sync-config.plugin";
 export { syncTypes, type SyncTypesOptions } from "./dev/sync-types.plugin";
+export { syncDiffs, type SyncDiffsOptions } from "./dev/sync-diffs.plugin";