From 9fabaab31c561f7dadbb88caff392c501be9ec36 Mon Sep 17 00:00:00 2001
From: EugeniyKiyashko <EugeniyKiyashko@users.noreply.github.com>
Date: Wed, 9 Sep 2026 14:53:45 +0400
Subject: [PATCH 1/2] Core: remove m_ prefix from events_strategy file

---
 .../core/{m_events_strategy.ts => events_strategy.ts}           | 0
 .../devextreme/js/__internal/integration/knockout/validation.ts | 2 +-
 packages/devextreme/js/core/events_strategy.js                  | 2 +-
 3 files changed, 2 insertions(+), 2 deletions(-)
 rename packages/devextreme/js/__internal/core/{m_events_strategy.ts => events_strategy.ts} (100%)

diff --git a/packages/devextreme/js/__internal/core/m_events_strategy.ts b/packages/devextreme/js/__internal/core/events_strategy.ts
similarity index 100%
rename from packages/devextreme/js/__internal/core/m_events_strategy.ts
rename to packages/devextreme/js/__internal/core/events_strategy.ts
diff --git a/packages/devextreme/js/__internal/integration/knockout/validation.ts b/packages/devextreme/js/__internal/integration/knockout/validation.ts
index 945c78a188ed..ccdd10307bd4 100644
--- a/packages/devextreme/js/__internal/integration/knockout/validation.ts
+++ b/packages/devextreme/js/__internal/integration/knockout/validation.ts
@@ -1,6 +1,6 @@
+import { EventsStrategy } from '@ts/core/events_strategy';
 import { Guid } from '@ts/core/guid';
 import Class from '@ts/core/m_class';
-import { EventsStrategy } from '@ts/core/m_events_strategy';
 import { Deferred } from '@ts/core/utils/m_deferred';
 import { extend } from '@ts/core/utils/m_extend';
 import { each, map } from '@ts/core/utils/m_iterator';
diff --git a/packages/devextreme/js/core/events_strategy.js b/packages/devextreme/js/core/events_strategy.js
index d28bcbfc9214..dd556120ee5f 100644
--- a/packages/devextreme/js/core/events_strategy.js
+++ b/packages/devextreme/js/core/events_strategy.js
@@ -1,2 +1,2 @@
 // deprecated
-export { EventsStrategy } from '../__internal/core/m_events_strategy';
+export { EventsStrategy } from '../__internal/core/events_strategy';

From bf6ec98f030c975d00da9e2acab2f82bacd33d59 Mon Sep 17 00:00:00 2001
From: EugeniyKiyashko <EugeniyKiyashko@users.noreply.github.com>
Date: Thu, 10 Sep 2026 17:02:23 +0400
Subject: [PATCH 2/2] Core: fix eslint/ts errors after rename events_strategy

---
 .../js/__internal/core/events_strategy.ts     | 52 ++++++++++++++-----
 1 file changed, 40 insertions(+), 12 deletions(-)

diff --git a/packages/devextreme/js/__internal/core/events_strategy.ts b/packages/devextreme/js/__internal/core/events_strategy.ts
index 8a5e59ab5192..fc3ef62ca88d 100644
--- a/packages/devextreme/js/__internal/core/events_strategy.ts
+++ b/packages/devextreme/js/__internal/core/events_strategy.ts
@@ -1,33 +1,61 @@
-import Callbacks from '@js/core/utils/callbacks';
 import { each } from '@js/core/utils/iterator';
 import { isFunction, isPlainObject } from '@js/core/utils/type';
+import { Callbacks } from '@ts/core/utils/m_callbacks';
 
-export class EventsStrategy {
-  _events: any;
+type EventHandler = Function;
 
-  _owner: any;
+type EventHandlers = Record<string, EventHandler | undefined>;
 
-  _options: any;
+interface EventCallbacks {
+  add: (fn?: EventHandler) => void;
+  originalAdd?: (fn?: EventHandler) => void;
+  remove: (fn?: EventHandler) => void;
+  has: () => boolean;
+  empty: () => void;
+  fireWith: (context: unknown, args?: ArrayLike<unknown>) => void;
+}
+
+export interface EventsStrategyOptions {
+  syncStrategy?: boolean;
+}
+
+export interface EventsStrategyInterface {
+  on: (eventName: string | EventHandlers, eventHandler?: EventHandler) => void;
+  off: (eventName: string, eventHandler?: EventHandler) => void;
+  fireEvent: (eventName: string, eventArgs?: ArrayLike<unknown>) => unknown;
+  hasEvent: (eventName: string) => boolean;
+  dispose: () => void;
+}
+
+export class EventsStrategy implements EventsStrategyInterface {
+  _events: Record<string, EventCallbacks>;
+
+  _owner: unknown;
+
+  _options: EventsStrategyOptions;
 
-  constructor(owner, options = {}) {
+  constructor(owner: unknown, options: EventsStrategyOptions = {}) {
     this._events = {};
     this._owner = owner;
     this._options = options;
   }
 
-  static create(owner, strategy) {
+  static create(
+    owner: unknown,
+    strategy?: EventsStrategyInterface | ((owner: unknown) => EventsStrategyInterface),
+  ): EventsStrategyInterface {
     if (strategy) {
       return isFunction(strategy) ? strategy(owner) : strategy;
     }
     return new EventsStrategy(owner);
   }
 
-  hasEvent(eventName) {
+  hasEvent(eventName: string): boolean {
     const callbacks = this._events[eventName];
     return callbacks ? callbacks.has() : false;
   }
 
-  fireEvent(eventName, eventArgs) {
+  fireEvent(eventName: string, eventArgs?: ArrayLike<unknown>): unknown {
     const callbacks = this._events[eventName];
     if (callbacks) {
       callbacks.fireWith(this._owner, eventArgs);
@@ -35,7 +63,7 @@ export class EventsStrategy {
     return this._owner;
   }
 
-  on(eventName, eventHandler) {
+  on(eventName: string | EventHandlers, eventHandler?: EventHandler): void {
     if (isPlainObject(eventName)) {
       each(eventName, (e, h) => {
         this.on(e, h);
@@ -55,7 +83,7 @@ export class EventsStrategy {
     }
   }
 
-  off(eventName, eventHandler) {
+  off(eventName: string, eventHandler?: EventHandler): void {
     const callbacks = this._events[eventName];
     if (callbacks) {
       if (isFunction(eventHandler)) {
@@ -66,7 +94,7 @@ export class EventsStrategy {
     }
   }
 
-  dispose() {
+  dispose(): void {
     each(this._events, (eventName, event) => {
       event.empty();
     });