From 83a8db34732da54d019f43897232ceecd6b84e01 Mon Sep 17 00:00:00 2001
From: Andrew Musgrave <andrew.musgrave@shopify.com>
Date: Wed, 14 Aug 2019 13:55:09 -0400
Subject: [PATCH] Removed RTG from ContextualSaveBar and replaced it with a
 custom CSSAnimation component

---
 src/components/Frame/Frame.scss               | 18 ----
 src/components/Frame/Frame.tsx                | 41 +++------
 .../components/CSSAnimation/CSSAnimation.scss | 11 +++
 .../components/CSSAnimation/CSSAnimation.tsx  | 88 +++++++++++++++++++
 .../Frame/components/CSSAnimation/index.ts    |  1 +
 src/components/Frame/components/index.ts      |  1 +
 6 files changed, 113 insertions(+), 47 deletions(-)
 create mode 100644 src/components/Frame/components/CSSAnimation/CSSAnimation.scss
 create mode 100644 src/components/Frame/components/CSSAnimation/CSSAnimation.tsx
 create mode 100644 src/components/Frame/components/CSSAnimation/index.ts

diff --git a/src/components/Frame/Frame.scss b/src/components/Frame/Frame.scss
index 090334b8..ec18f1b1 100644
--- a/src/components/Frame/Frame.scss
+++ b/src/components/Frame/Frame.scss
@@ -114,24 +114,6 @@ $skip-vertical-offset: rem(10px);
   width: 100%;
 }
 
-.ContextualSaveBar-enter {
-  opacity: 0;
-}
-
-.ContextualSaveBar-enterActive {
-  opacity: 1;
-  transition: opacity duration() easing(out);
-}
-
-.ContextualSaveBar-exit {
-  opacity: 1;
-}
-
-.ContextualSaveBar-exitActive {
-  opacity: 0;
-  transition: opacity duration() easing(out);
-}
-
 .Main {
   flex: 1;
   display: flex;
diff --git a/src/components/Frame/Frame.tsx b/src/components/Frame/Frame.tsx
index b7c1de96..ca7e4add 100644
--- a/src/components/Frame/Frame.tsx
+++ b/src/components/Frame/Frame.tsx
@@ -20,7 +20,13 @@ import {
   ToastID,
   ToastPropsWithID,
 } from '../../utilities/frame';
-import {ToastManager, Loading, ContextualSaveBar} from './components';
+import {
+  ToastManager,
+  Loading,
+  ContextualSaveBar,
+  CSSAnimation,
+  AnimationType,
+} from './components';
 
 import styles from './Frame.scss';
 
@@ -72,7 +78,6 @@ class Frame extends React.PureComponent<CombinedProps, State> {
   private contextualSaveBar: ContextualSaveBarProps | null;
   private globalRibbonContainer: HTMLDivElement | null = null;
   private navigationNode = createRef<HTMLDivElement>();
-  private contextualSaveBarNode = createRef<HTMLDivElement>();
   private skipToMainContentTargetNode = React.createRef<HTMLAnchorElement>();
 
   componentDidMount() {
@@ -161,23 +166,13 @@ class Frame extends React.PureComponent<CombinedProps, State> {
       ) : null;
 
     const contextualSaveBarMarkup = (
-      <CSSTransition
-        findDOMNode={this.findContextualSaveBarNode}
-        appear
-        exit
+      <CSSAnimation
         in={showContextualSaveBar}
-        timeout={300}
-        classNames={contextualSaveBarTransitionClasses}
-        mountOnEnter
-        unmountOnExit
+        className={styles.ContextualSaveBar}
+        type={AnimationType.Fade}
       >
-        <div
-          className={styles.ContextualSaveBar}
-          ref={this.contextualSaveBarNode}
-        >
-          <ContextualSaveBar {...this.contextualSaveBar} />
-        </div>
-      </CSSTransition>
+        <ContextualSaveBar {...this.contextualSaveBar} />
+      </CSSAnimation>
     );
 
     const topBarMarkup = topBar ? (
@@ -402,10 +397,6 @@ class Frame extends React.PureComponent<CombinedProps, State> {
   private findNavigationNode = () => {
     return this.navigationNode.current;
   };
-
-  private findContextualSaveBarNode = () => {
-    return this.contextualSaveBarNode.current;
-  };
 }
 
 const navTransitionClasses = {
@@ -416,14 +407,6 @@ const navTransitionClasses = {
   exitActive: classNames(styles['Navigation-exitActive']),
 };
 
-const contextualSaveBarTransitionClasses = {
-  enter: classNames(styles['ContextualSaveBar-enter']),
-  enterActive: classNames(styles['ContextualSaveBar-enterActive']),
-  enterDone: classNames(styles['ContextualSaveBar-enterActive']),
-  exit: classNames(styles['ContextualSaveBar-exit']),
-  exitActive: classNames(styles['ContextualSaveBar-exitActive']),
-};
-
 function isMobileView() {
   return navigationBarCollapsed().matches;
 }
diff --git a/src/components/Frame/components/CSSAnimation/CSSAnimation.scss b/src/components/Frame/components/CSSAnimation/CSSAnimation.scss
new file mode 100644
index 00000000..1648f34f
--- /dev/null
+++ b/src/components/Frame/components/CSSAnimation/CSSAnimation.scss
@@ -0,0 +1,11 @@
+@import '../../../../styles/common';
+
+.startFade {
+  opacity: 0;
+  will-change: opacity;
+  transition: opacity duration(slow) easing(out);
+}
+
+.endFade {
+  opacity: 1;
+}
diff --git a/src/components/Frame/components/CSSAnimation/CSSAnimation.tsx b/src/components/Frame/components/CSSAnimation/CSSAnimation.tsx
new file mode 100644
index 00000000..e1e4c436
--- /dev/null
+++ b/src/components/Frame/components/CSSAnimation/CSSAnimation.tsx
@@ -0,0 +1,88 @@
+import React, {useRef, useState, useEffect} from 'react';
+import {classNames, variationName} from '../../../../utilities/css';
+
+import styles from './CSSAnimation.scss';
+
+export enum AnimationType {
+  Fade = 'fade',
+}
+
+export interface Props {
+  in: boolean;
+  className: string;
+  type: AnimationType;
+  children?: React.ReactNode;
+}
+
+enum TransitionStatus {
+  Entering = 'entering',
+  Entered = 'entered',
+  Exiting = 'exiting',
+  Exited = 'exited',
+}
+
+export default function Collapsible({
+  in: inProp,
+  className,
+  type,
+  children,
+}: Props) {
+  const [transitionStatus, setTransitionStatus] = useState(
+    inProp ? TransitionStatus.Entering : TransitionStatus.Exited,
+  );
+  const isMounted = useRef(false);
+  const node = useRef<HTMLDivElement>(null);
+
+  useEffect(
+    () => {
+      if (!isMounted.current) return;
+      transitionStatus === TransitionStatus.Entering &&
+        changeTransitionStatus(TransitionStatus.Entered);
+    },
+    [transitionStatus],
+  );
+
+  useEffect(
+    () => {
+      if (!isMounted.current) return;
+      inProp && changeTransitionStatus(TransitionStatus.Entering);
+      !inProp && changeTransitionStatus(TransitionStatus.Exiting);
+    },
+    [inProp],
+  );
+
+  useEffect(() => {
+    isMounted.current = true;
+  }, []);
+
+  const wrapperClassName = classNames(
+    className,
+    styles[variationName('start', type)],
+    inProp && styles[variationName('end', type)],
+  );
+
+  const content =
+    transitionStatus === TransitionStatus.Exited && !inProp ? null : children;
+
+  return (
+    <div
+      className={wrapperClassName}
+      ref={node}
+      onTransitionEnd={handleTransitionEnd}
+    >
+      {content}
+    </div>
+  );
+
+  function handleTransitionEnd() {
+    transitionStatus === TransitionStatus.Exiting &&
+      changeTransitionStatus(TransitionStatus.Exited);
+  }
+
+  function changeTransitionStatus(transitionStatus: TransitionStatus) {
+    setTransitionStatus(transitionStatus);
+    // Forcing a reflow to enable the animation
+    if (transitionStatus === TransitionStatus.Entering)
+      node.current && node.current.getBoundingClientRect();
+  }
+}
diff --git a/src/components/Frame/components/CSSAnimation/index.ts b/src/components/Frame/components/CSSAnimation/index.ts
new file mode 100644
index 00000000..942b2b02
--- /dev/null
+++ b/src/components/Frame/components/CSSAnimation/index.ts
@@ -0,0 +1 @@
+export {default, AnimationType} from './CSSAnimation';
diff --git a/src/components/Frame/components/index.ts b/src/components/Frame/components/index.ts
index e883cd4e..6b364c71 100644
--- a/src/components/Frame/components/index.ts
+++ b/src/components/Frame/components/index.ts
@@ -9,3 +9,4 @@ export {
 } from './ToastManager';
 export {default as Loading, Props as LoadingProps} from './Loading';
 export {default as ContextualSaveBar} from './ContextualSaveBar';
+export {default as CSSAnimation, AnimationType} from './CSSAnimation';