Replace switch with falsyness checks

Author: rslawik

src/material/datepicker/calendar.ts

@@ -418,15 +418,9 @@ export class MatCalendar<D> implements AfterContentInit, AfterViewChecked, OnDes
 
   /** Returns the component instance that corresponds to the current calendar view. */
   private _getCurrentViewComponent(): MatMonthView<D> | MatYearView<D> | MatMultiYearView<D> {
-    // The return type must be a union to ensure that the Closure compiler does not optimize the
-    // calls to _init(). See https://github.com/angular/components/issues/22996.
-    switch (this.currentView) {
-      case 'month':
-        return this.monthView;
-      case 'year':
-        return this.yearView;
-      case 'multi-year':
-        return this.multiYearView;
-    }
+    // The return type is explicitly written as a union to ensure that the Closure compiler does
+    // not optimize the calls to _init(). Without the explict return type, TypeScript narrows it
+    // to only the first component type. See https://github.com/angular/components/issues/22996.
+    return this.monthView || this.yearView || this.multiYearView;
   }
 }