fix: address the scenario when extrenal type parameter is passed to DeepPartial (T1263537) (#29044)

Author: VasilyStrelyaev

e2e/compilation-cases/T1263537.ts

@@ -0,0 +1,36 @@
+import ODataStore from 'devextreme/data/odata/store';
+import CustomStore from 'devextreme/data/custom_store';
+import { Store } from 'devextreme/data/store';
+import { LoadOptions } from 'devextreme/data';
+
+// Remove the 'ts-expect-error' below to see the current issue:
+// Entity is not compatible with DeepPartial<Entity>
+function initCustomStore<Entity, Id>(oDataStore: ODataStore<Entity, Id>): Store<Entity, Id> {
+  const customStore = new CustomStore<Entity, Id>({
+    key: 'id',
+    byKey: (key: Id) => oDataStore.byKey(key),
+    insert: (e: Entity) => oDataStore.insert(e),
+    load: (options: LoadOptions<Entity>) => oDataStore.load(options),
+    remove: (key: Id) => oDataStore.remove(key),
+    totalCount: (obj) => oDataStore.totalCount(obj),
+    update: (key: Id, updated: Entity) => oDataStore.update(key, updated),
+  });
+  return customStore;
+}
+
+// If this TS issue is fixed: https://github.com/microsoft/TypeScript/issues/23132
+// there will be a good workaround to use type constraints to make such an assignment possible
+function initCustomStore3<Entity extends object, Id>(
+  oDataStore: ODataStore<Entity, Id>,
+): Store<Entity, Id> {
+  const customStore = new CustomStore<Entity, Id>({
+    key: 'id',
+    byKey: (key: Id) => oDataStore.byKey(key),
+    insert: (e: Entity) => oDataStore.insert(e),
+    load: (options: LoadOptions<Entity>) => oDataStore.load(options),
+    remove: (key: Id) => oDataStore.remove(key),
+    totalCount: (obj) => oDataStore.totalCount(obj),
+    update: (key: Id, updated: Entity) => oDataStore.update(key, updated),
+  });
+  return customStore;
+}

packages/devextreme/js/core/index.d.ts

@@ -20,9 +20,9 @@ export type Xor<T1, T2 = never, T3 = never, T4 = never, T5 = never, T6 = never,
   | Seal<T9, KeysOf<T1, T2, T3, T4, T5, T6, T7, T8>>;
 
 export type Scalar = undefined | null | string | String | number | Number | bigint | BigInteger | boolean | Boolean | Date | Function | Symbol | Array<unknown>;
-export type DeepPartial<T> = T extends Scalar ? T : {
+export type DeepPartial<T> = T | (T extends Scalar ? T : {
   [P in keyof T]?: DeepPartial<T[P]>;
-};
+});
 
 type ItemType<T> = T extends (infer TItem)[] ? TItem : T;
 type Property<T, TPropName extends string> = T extends Partial<Record<TPropName, infer TValue>> ? TValue : never;

packages/devextreme/ts/dx.all.d.ts

@@ -4850,11 +4850,13 @@ declare module DevExpress.core {
   /**
    * @deprecated Attention! This type is for internal purposes only. If you used it previously, please submit a ticket to our {@link https://supportcenter.devexpress.com/ticket/create Support Center}. We will check if there is an alternative solution.
    */
-  export type DeepPartial<T> = T extends Scalar
-    ? T
-    : {
-        [P in keyof T]?: DeepPartial<T[P]>;
-      };
+  export type DeepPartial<T> =
+    | T
+    | (T extends Scalar
+        ? T
+        : {
+            [P in keyof T]?: DeepPartial<T[P]>;
+          });
   /**
    * [descr:DefaultOptionsRule]
    */