From 20a034e73a12e44e7ef4e96aa8a3396e946a3f80 Mon Sep 17 00:00:00 2001
From: Karl Seamon <bannanafiend@gmail.com>
Date: Thu, 4 Nov 2021 13:14:08 -0400
Subject: [PATCH] perf(multiple): Remove IE 11 cruft from table, column-resize,
 and popover-edit.

---
 .../column-resize/column-resize.ts            |  8 ++----
 src/cdk-experimental/popover-edit/polyfill.ts | 28 ++-----------------
 .../popover-edit/public-api.ts                |  2 +-
 src/cdk/table/cell.ts                         |  7 +----
 4 files changed, 6 insertions(+), 39 deletions(-)

diff --git a/src/cdk-experimental/column-resize/column-resize.ts b/src/cdk-experimental/column-resize/column-resize.ts
index ed4146084072..a1e354f95445 100644
--- a/src/cdk-experimental/column-resize/column-resize.ts
+++ b/src/cdk-experimental/column-resize/column-resize.ts
@@ -10,7 +10,7 @@ import {AfterViewInit, Directive, ElementRef, NgZone, OnDestroy} from '@angular/
 import {fromEvent, merge, Subject} from 'rxjs';
 import {filter, map, mapTo, pairwise, startWith, take, takeUntil} from 'rxjs/operators';
 
-import {_closest, _matches} from '@angular/cdk-experimental/popover-edit';
+import {_closest} from '@angular/cdk-experimental/popover-edit';
 
 import {ColumnResizeNotifier, ColumnResizeNotifierSource} from './column-resize-notifier';
 import {HEADER_CELL_SELECTOR, RESIZE_OVERLAY_SELECTOR} from './selectors';
@@ -80,11 +80,7 @@ export abstract class ColumnResize implements AfterViewInit, OnDestroy {
         .subscribe(this.eventDispatcher.headerCellHovered);
       fromEvent<MouseEvent>(element, 'mouseleave')
         .pipe(
-          filter(
-            event =>
-              !!event.relatedTarget &&
-              !_matches(event.relatedTarget as Element, RESIZE_OVERLAY_SELECTOR),
-          ),
+          filter(event => !!(event.relatedTarget as Element)?.matches(RESIZE_OVERLAY_SELECTOR)),
           mapTo(null),
           takeUntil(this.destroyed),
         )
diff --git a/src/cdk-experimental/popover-edit/polyfill.ts b/src/cdk-experimental/popover-edit/polyfill.ts
index d71e8cfaa96a..efe2f36375ca 100644
--- a/src/cdk-experimental/popover-edit/polyfill.ts
+++ b/src/cdk-experimental/popover-edit/polyfill.ts
@@ -6,14 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-/** IE 11 compatible matches implementation. */
-export function matches(element: Element, selector: string): boolean {
-  return element.matches
-    ? element.matches(selector)
-    : (element as any)['msMatchesSelector'](selector);
-}
-
-/** IE 11 compatible closest implementation that is able to start from non-Element Nodes. */
+/** closest implementation that is able to start from non-Element Nodes. */
 export function closest(
   element: EventTarget | Element | null | undefined,
   selector: string,
@@ -27,22 +20,5 @@ export function closest(
     curr = curr.parentNode;
   }
 
-  return (
-    curr &&
-    ((hasNativeClosest
-      ? curr.closest(selector)
-      : polyfillClosest(curr, selector)) as Element | null)
-  );
+  return curr?.closest(selector) ?? null;
 }
-
-/** Polyfill for browsers without Element.closest. */
-function polyfillClosest(element: Element, selector: string): Element | null {
-  let curr: Node | null = element;
-  while (curr != null && !(curr instanceof Element && matches(curr, selector))) {
-    curr = curr.parentNode;
-  }
-
-  return (curr || null) as Element | null;
-}
-
-const hasNativeClosest = !!Element.prototype.closest;
diff --git a/src/cdk-experimental/popover-edit/public-api.ts b/src/cdk-experimental/popover-edit/public-api.ts
index db5e67108b82..96346bf8c856 100644
--- a/src/cdk-experimental/popover-edit/public-api.ts
+++ b/src/cdk-experimental/popover-edit/public-api.ts
@@ -17,4 +17,4 @@ export * from './table-directives';
 
 // Private to Angular Components
 export {CELL_SELECTOR as _CELL_SELECTOR} from './constants';
-export {closest as _closest, matches as _matches} from './polyfill';
+export {closest as _closest} from './polyfill';
diff --git a/src/cdk/table/cell.ts b/src/cdk/table/cell.ts
index 22bf3c9c93d9..a9d399214559 100644
--- a/src/cdk/table/cell.ts
+++ b/src/cdk/table/cell.ts
@@ -153,12 +153,7 @@ export class CdkColumnDef extends _CdkColumnDefBase implements CanStick {
 /** Base class for the cells. Adds a CSS classname that identifies the column it renders in. */
 export class BaseCdkCell {
   constructor(columnDef: CdkColumnDef, elementRef: ElementRef) {
-    // If IE 11 is dropped before we switch to setting a single class name, change to multi param
-    // with destructuring.
-    const classList = elementRef.nativeElement.classList;
-    for (const className of columnDef._columnCssClassName) {
-      classList.add(className);
-    }
+    elementRef.nativeElement.classList.add(...columnDef._columnCssClassName);
   }
 }