fix(material/paginator): emit events when page index is updated

Author: andrewseguin

src/material/paginator/paginator.ts

@@ -137,8 +137,7 @@ export class MatPaginator implements OnInit, OnDestroy {
     return this._pageIndex;
   }
   set pageIndex(value: number) {
-    this._pageIndex = Math.max(value || 0, 0);
-    this._changeDetectorRef.markForCheck();
+    this._navigate(value);
   }
   private _pageIndex = 0;
 
@@ -306,11 +305,8 @@ export class MatPaginator implements OnInit, OnDestroy {
     // Current page needs to be updated to reflect the new page size. Navigate to the page
     // containing the previous page's first item.
     const startIndex = this.pageIndex * this.pageSize;
-    const previousPageIndex = this.pageIndex;
-
-    this.pageIndex = Math.floor(startIndex / pageSize) || 0;
     this.pageSize = pageSize;
-    this._emitPageEvent(previousPageIndex);
+    this.pageIndex = Math.floor(startIndex / pageSize) || 0;
   }
 
   /** Checks whether the buttons for going forwards should be disabled. */
@@ -361,11 +357,11 @@ export class MatPaginator implements OnInit, OnDestroy {
 
   /** Navigates to a specific page index. */
   private _navigate(index: number) {
-    const previousIndex = this.pageIndex;
-
-    if (index !== previousIndex) {
-      this.pageIndex = index;
-      this._emitPageEvent(previousIndex);
+    if (index !== this.pageIndex) {
+      const previousPageIndex = this._pageIndex;
+      this._pageIndex = Math.max(index || 0, 0);
+      this._changeDetectorRef.markForCheck();
+      this._emitPageEvent(previousPageIndex);
     }
   }
 

src/material/table/table.spec.ts

@@ -566,6 +566,18 @@ describe('MatTable', () => {
         ['a_10', 'b_10', 'c_10'],
         ['Footer A', 'Footer B', 'Footer C'],
       ]);
+
+      component.paginator.pageIndex = 0;
+      fixture.detectChanges();
+      expectTableToMatchContent(tableElement, [
+        ['Column A', 'Column B', 'Column C'],
+        ['a_1', 'b_1', 'c_1'],
+        ['a_2', 'b_2', 'c_2'],
+        ['a_3', 'b_3', 'c_3'],
+        ['a_4', 'b_4', 'c_4'],
+        ['a_5', 'b_5', 'c_5'],
+        ['Footer A', 'Footer B', 'Footer C'],
+      ]);
     }));
 
     it('should sort strings with numbers larger than MAX_SAFE_INTEGER correctly', () => {