From de1fefa78dd2c98051a24084fa3cc365b661a460 Mon Sep 17 00:00:00 2001
From: Chandler Prall <chandler.prall@gmail.com>
Date: Mon, 6 Jul 2020 13:32:09 -0600
Subject: [PATCH 1/2] Bugfixes for resizable panels including arrow keys,
 nested panels, and mixed button sizes

---
 .../resizable_container/context.tsx           | 13 ++++++++++
 src/components/resizable_container/helpers.ts | 24 +++++++++----------
 .../resizable_container/resizable_button.tsx  | 22 +++++++++++++++++
 .../resizable_container.tsx                   |  3 ++-
 4 files changed, 48 insertions(+), 14 deletions(-)

diff --git a/src/components/resizable_container/context.tsx b/src/components/resizable_container/context.tsx
index 708db17a0ea..1be0fbd052d 100644
--- a/src/components/resizable_container/context.tsx
+++ b/src/components/resizable_container/context.tsx
@@ -28,6 +28,7 @@ export interface EuiResizablePanelController {
 
 export class EuiResizablePanelRegistry {
   private panels: { [key: string]: EuiResizablePanelController } = {};
+  private resizerRefs = new Set<HTMLElement>();
 
   registerPanel(panel: EuiResizablePanelController) {
     this.panels[panel.id] = panel;
@@ -37,10 +38,22 @@ export class EuiResizablePanelRegistry {
     delete this.panels[id];
   }
 
+  registerResizerRef(resizerRef: HTMLElement) {
+    this.resizerRefs.add(resizerRef);
+  }
+
+  deregisterResizerRef(resizerRef: HTMLElement) {
+    this.resizerRefs.delete(resizerRef);
+  }
+
   getResizerSiblings(prevPanelId: string, nextPanelId: string) {
     return [this.panels[prevPanelId], this.panels[nextPanelId]];
   }
 
+  getAllResizers() {
+    return Array.from(this.resizerRefs);
+  }
+
   fetchAllPanels(
     prevPanelId: string,
     nextPanelId: string,
diff --git a/src/components/resizable_container/helpers.ts b/src/components/resizable_container/helpers.ts
index 5e271c33f21..27caa43407d 100644
--- a/src/components/resizable_container/helpers.ts
+++ b/src/components/resizable_container/helpers.ts
@@ -77,15 +77,13 @@ export const useContainerCallbacks = ({
 
   const getResizerButtonsSize = useCallback(() => {
     // get sum of all of resizer button sizes to proper calculate panels ratio
-    const allResizers = containerRef.current!.getElementsByClassName(
-      'euiResizableButton'
-    ) as HTMLCollectionOf<HTMLButtonElement>;
-    const size = isHorizontal
-      ? allResizers[0].offsetWidth
-      : allResizers[0].offsetHeight;
-
-    return size * allResizers.length;
-  }, [containerRef, isHorizontal]);
+    const allResizers = registryRef.current.getAllResizers();
+    return allResizers.reduce(
+      (size, resizer) =>
+        size + (isHorizontal ? resizer.offsetWidth : resizer.offsetHeight),
+      0
+    );
+  }, [registryRef, isHorizontal]);
 
   const onMouseDown = useCallback(
     (event: EuiResizableButtonMouseEvent) => {
@@ -150,16 +148,16 @@ export const useContainerCallbacks = ({
           nextPanelId,
           containerSize - resizersSize
         );
-        if (prevPanelSize !== nextPanelSize && onPanelWidthChange) {
+
+        if (onPanelWidthChange) {
           onPanelWidthChange({
             ...panelObject,
             [prevPanelId]: prevPanelSize,
             [nextPanelId]: nextPanelSize,
           });
-
-          prevPanel.setSize(prevPanelSize);
-          nextPanel.setSize(nextPanelSize);
         }
+        prevPanel.setSize(prevPanelSize);
+        nextPanel.setSize(nextPanelSize);
       }
     },
     // `setState` is safe to omit from `useCallback`
diff --git a/src/components/resizable_container/resizable_button.tsx b/src/components/resizable_container/resizable_button.tsx
index 8806a0a2324..9d29ad319ab 100644
--- a/src/components/resizable_container/resizable_button.tsx
+++ b/src/components/resizable_container/resizable_button.tsx
@@ -23,11 +23,14 @@ import React, {
   KeyboardEvent,
   MouseEvent,
   TouchEvent,
+  useCallback,
+  useRef,
 } from 'react';
 import classNames from 'classnames';
 
 import { CommonProps } from '../common';
 import { EuiI18n } from '../i18n';
+import { EuiResizablePanelRegistry } from './context';
 
 export type EuiResizableButtonMouseEvent =
   | MouseEvent<HTMLButtonElement>
@@ -41,6 +44,7 @@ interface EuiResizableButtonControls {
   onMouseDown: (eve: EuiResizableButtonMouseEvent) => void;
   onTouchStart: (eve: EuiResizableButtonMouseEvent) => void;
   isHorizontal: boolean;
+  registryRef: React.MutableRefObject<EuiResizablePanelRegistry>;
 }
 
 export interface EuiResizableButtonProps
@@ -69,6 +73,7 @@ export const EuiResizableButton: FunctionComponent<EuiResizableButtonProps> = ({
   isHorizontal,
   className,
   size = 'm',
+  registryRef,
   ...rest
 }) => {
   const classes = classNames(
@@ -81,6 +86,22 @@ export const EuiResizableButton: FunctionComponent<EuiResizableButtonProps> = ({
     className
   );
 
+  const previousRef = useRef<HTMLElement>();
+  const onRef = useCallback(
+    (ref: HTMLElement | null) => {
+      if (ref) {
+        previousRef.current = ref;
+        registryRef!.current.registerResizerRef(ref);
+      } else {
+        if (previousRef.current != null) {
+          registryRef!.current.deregisterResizerRef(previousRef.current);
+          previousRef.current = undefined;
+        }
+      }
+    },
+    [registryRef]
+  );
+
   const setFocus = (e: MouseEvent<HTMLButtonElement>) =>
     e.currentTarget.focus();
 
@@ -96,6 +117,7 @@ export const EuiResizableButton: FunctionComponent<EuiResizableButtonProps> = ({
       ]}>
       {([horizontalResizerAriaLabel, verticalResizerAriaLabel]: string[]) => (
         <button
+          ref={onRef}
           aria-label={
             isHorizontal ? horizontalResizerAriaLabel : verticalResizerAriaLabel
           }
diff --git a/src/components/resizable_container/resizable_container.tsx b/src/components/resizable_container/resizable_container.tsx
index d34c63a27a9..2721ac2b17a 100644
--- a/src/components/resizable_container/resizable_container.tsx
+++ b/src/components/resizable_container/resizable_container.tsx
@@ -126,8 +126,9 @@ export const EuiResizableContainer: FunctionComponent<
       onMouseDown,
       onTouchStart: onMouseDown,
       isHorizontal,
+      registryRef,
     }),
-    [onKeyDown, onMouseDown, isHorizontal]
+    [onKeyDown, onMouseDown, isHorizontal, registryRef]
   );
 
   const EuiResizablePanel = useCallback(

From 47786cf68923033bc560252c9670d098fc2b007e Mon Sep 17 00:00:00 2001
From: Chandler Prall <chandler.prall@gmail.com>
Date: Mon, 6 Jul 2020 13:55:49 -0600
Subject: [PATCH 2/2] changelog

---
 CHANGELOG.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 05ebb6b7f1c..03548638847 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,11 @@
 - Added `isClearable` and `placeholder` options to `EuiColorPicker` ([#3689](https://github.com/elastic/eui/pull/3689))
 - Added SASS helper files for EUI theme globals ([#3691](https://github.com/elastic/eui/pull/3691))
 
+**Bug fixes**
+
+- Fixed a bug in `EuiResizableContainer` preventing nested containers ([#3699](https://github.com/elastic/eui/pull/3699))
+- Fixed a bug in `EuiResizableContainer` preventing resizing by arrow keys in some cases ([#3699](https://github.com/elastic/eui/pull/3699))
+
 ## [`26.3.0`](https://github.com/elastic/eui/tree/v26.3.0)
 
 - Expanded `EuiBasicTable`'s default action's name configuration to accept any React node ([#3688](https://github.com/elastic/eui/pull/3688))