fixup! after rebase

types/__test__.ts

@@ -27,7 +27,16 @@ const db = new DataSource('db', {connector: 'memory'});
   // An operation hook can be installed
   Data.observe('before save', async ctx => {});
 
+  // Context is typed and provides `Model` property
+  Data.observe('before save', async ctx => {
+    console.log(ctx.Model.modelName);
+  });
+
   // ModelBaseClass can be assigned to `typeof ModelBase`
+  // Please note that both `ModelBaseClass` and typeof ModelBase`
+  // are different ways how to describe a class constructor of a model.
+  // In this test we are verifying that the value retunred by `createModel`
+  // can be assigned to both types.
   const modelTypeof: typeof ModelBase = Data;
   const modelCls: ModelBaseClass = modelTypeof;
 });
@@ -50,7 +59,16 @@ const db = new DataSource('db', {connector: 'memory'});
     next(new Error('test error'));
   });
 
+  // ctx.Model is a PersistedModel class constructor
+  Product.observe('before save', async ctx => {
+    await ctx.Model.findOne();
+  });
+
   // PersistedModelClass can be assigned to `typeof PersistedModel`
+  // Please note that both `PersistedModelClass` and typeof PersistedModel`
+  // are different ways how to describe a class constructor of a model.
+  // In this test we are verifying that the value retunred by `createModel`
+  // can be assigned to both types.
   const modelTypeof: typeof PersistedModel = Product;
   const modelCls: PersistedModelClass = modelTypeof;
 });
@@ -64,4 +82,9 @@ const db = new DataSource('db', {connector: 'memory'});
 
   // An operation hook can be installed
   CacheItem.observe('before save', async ctx => {});
+
+  // ctx.Model is a KeyValueModel class constructor
+  CacheItem.observe('before save', async ctx => {
+    await ctx.Model.expire('key', 100);
+  });
 });

types/model.d.ts

@@ -6,7 +6,7 @@
 import {EventEmitter} from 'events';
 import {AnyObject, Options} from './common';
 import {DataSource} from './datasource';
-import {Listener} from './observer-mixin';
+import {Listener, OperationHookContext} from './observer-mixin';
 
 /**
  * Property types
@@ -283,7 +283,7 @@ export declare class ModelBase {
   static observe<T extends typeof ModelBase>(
     this: T,
     operation: string,
-    listener: Listener
+    listener: Listener<OperationHookContext<T>>,
   ): void;
 
   /**
@@ -305,8 +305,8 @@ export declare class ModelBase {
   static removeObserver<T extends typeof ModelBase>(
     this: T,
     operation: string,
-    listener: Listener
-  ): Listener | undefined;
+    listener: Listener<OperationHookContext<T>>,
+  ): Listener<OperationHookContext<T>> | undefined;
 
   /**
    * Unregister all asynchronous observers for the given operation (event).

types/observer-mixin.d.ts

@@ -4,9 +4,9 @@
 // License text available at https://opensource.org/licenses/MIT
 
 import {Callback, PromiseOrVoid} from './common';
-import {PersistedModel, PersistedModelClass} from './persisted-model';
+import {ModelBase} from './model';
 
-export interface OperationHookContext<T extends typeof PersistedModel> {
+export interface OperationHookContext<T extends typeof ModelBase> {
   /**
    * The constructor of the model that triggered the operation.
    */
@@ -50,7 +50,11 @@ export interface ObserverMixin {
    * `this` set to the model constructor, e.g. `User`.
    * @end
    */
-  observe(operation: string, listener: Listener<OperationHookContext<PersistedModelClass>>): void;
+  observe<T extends typeof ModelBase>(
+    this: T,
+    operation: string,
+    listener: Listener<OperationHookContext<T>>,
+  ): void;
 
   /**
    * Unregister an asynchronous observer for the given operation (event).
@@ -68,7 +72,11 @@ export interface ObserverMixin {
    * @callback {function} listener The listener function.
    * @end
    */
-  removeObserver(operation: string, listener: Listener<OperationHookContext<PersistedModelClass>>): Listener<OperationHookContext<PersistedModelClass>> | undefined;
+  removeObserver<T extends typeof ModelBase>(
+    this: T,
+    operation: string,
+    listener: Listener<OperationHookContext<T>>,
+  ): Listener<OperationHookContext<T>> | undefined;
 
   /**
    * Unregister all asynchronous observers for the given operation (event).