From 75d1420ae428599c8abfae9e80f9e960b0edeaa1 Mon Sep 17 00:00:00 2001
From: Jordan Eldredge <jordan@jordaneldredge.com>
Date: Thu, 5 Dec 2019 22:15:36 -0800
Subject: [PATCH] Extract useOnClickAway

---
 js/components/PlaylistWindow/PlaylistMenu.tsx | 99 +++++++------------
 js/hooks.ts                                   | 37 +++++++
 2 files changed, 73 insertions(+), 63 deletions(-)

diff --git a/js/components/PlaylistWindow/PlaylistMenu.tsx b/js/components/PlaylistWindow/PlaylistMenu.tsx
index 8d34522e..62815f04 100644
--- a/js/components/PlaylistWindow/PlaylistMenu.tsx
+++ b/js/components/PlaylistWindow/PlaylistMenu.tsx
@@ -1,80 +1,53 @@
-import React from "react";
+import React, { useState, ReactNode, useCallback } from "react";
 import classnames from "classnames";
+import { useOnClickAway } from "../../hooks";
 
 import PlaylistMenuEnry from "./PlaylistMenuEntry";
 
 interface Props {
   id: string;
+  children: ReactNode | Array<ReactNode>;
 }
 
 interface State {
   selected: boolean;
 }
 
-export default class PlaylistMenu extends React.Component<Props, State> {
-  constructor(props: Props) {
-    super(props);
-    this.state = { selected: false };
-  }
+export default function PlaylistMenu(props: Props) {
+  const [selected, setSelected] = useState(false);
 
-  _handleClick = (e: React.MouseEvent<HTMLDivElement>) => {
-    const { target } = e;
-    if (!(target instanceof Element)) {
-      // TypeScript doesn't realize this will always be true
-      return;
-    }
-    const { selected } = this.state;
-    if (selected) {
-      this.setState({ selected: false });
-      return;
-    }
+  const [ref, setRef] = useState<Element | null>(null);
 
-    const handleClickOut = (ee: MouseEvent) => {
-      const clickOutTarget = ee.target;
-      if (!(clickOutTarget instanceof Element)) {
-        // TypeScript doesn't realize this will always be true
-        return;
-      }
-      // If the click is _not_ inside the menu.
-      if (!target.contains(clickOutTarget)) {
-        // If we've clicked on a Context Menu spawed inside this menu, it will
-        // register as an external click. However, hiding the menu will remove
-        // the Context Menu from the DOM. Therefore, we wait until the next
-        // event loop to actually hide ourselves.
-        setTimeout(() => {
-          // Close the menu
-          this.setState({ selected: false });
-        }, 0);
-        window.document.removeEventListener("click", handleClickOut, {
-          capture: true,
-        });
-      }
-    };
-    window.document.addEventListener("click", handleClickOut, {
-      capture: true,
-    });
+  const callback = useCallback(() => {
+    // If we've clicked on a Context Menu spawed inside this menu, it will
+    // register as an external click. However, hiding the menu will remove
+    // the Context Menu from the DOM. Therefore, we wait until the next
+    // event loop to actually hide ourselves.
+    setTimeout(() => {
+      // Close the menu
+      setSelected(false);
+    }, 0);
+  }, []);
 
-    this.setState({ selected: true });
-  };
+  useOnClickAway(ref, selected ? callback : null);
 
-  render() {
-    return (
-      <div
-        id={this.props.id}
-        className={classnames("playlist-menu", {
-          selected: this.state.selected,
-        })}
-        onClick={this._handleClick}
-      >
-        <div className="bar" />
-        {this.state.selected && (
-          <ul>
-            {React.Children.map(this.props.children, (child, i) => (
-              <PlaylistMenuEnry key={i}>{child}</PlaylistMenuEnry>
-            ))}
-          </ul>
-        )}
-      </div>
-    );
-  }
+  return (
+    <div
+      id={props.id}
+      className={classnames("playlist-menu", {
+        selected,
+      })}
+      ref={setRef}
+      onClick={() => setSelected(selected_ => !selected_)}
+    >
+      <div className="bar" />
+      {selected && (
+        <ul>
+          {React.Children.map(props.children, (child, i) => (
+            <PlaylistMenuEnry key={i}>{child}</PlaylistMenuEnry>
+          ))}
+        </ul>
+      )}
+    </div>
+  );
 }
diff --git a/js/hooks.ts b/js/hooks.ts
index c8b5546f..d5cc9f68 100644
--- a/js/hooks.ts
+++ b/js/hooks.ts
@@ -91,6 +91,43 @@ export function useIsHovered() {
   return { ref: setNode, hover };
 }
 
+export function useOnClickAway(
+  ref: Element | null,
+  callback: null | (() => void)
+) {
+  useEffect(() => {
+    if (ref == null || callback == null) {
+      return;
+    }
+
+    const handleClickOut = (ee: MouseEvent) => {
+      const clickOutTarget = ee.target;
+      if (!(clickOutTarget instanceof Element)) {
+        // TypeScript doesn't realize this will always be true
+        return;
+      }
+      if (ref.contains(clickOutTarget)) {
+        return;
+      }
+      // If the click is _not_ inside the menu.
+      callback();
+      window.document.removeEventListener("click", handleClickOut, {
+        capture: true,
+      });
+    };
+
+    window.document.addEventListener("click", handleClickOut, {
+      capture: true,
+    });
+
+    return () => {
+      window.document.removeEventListener("click", handleClickOut, {
+        capture: true,
+      });
+    };
+  }, [ref, callback]);
+}
+
 // TODO: Return useSelector directly and apply the type without wrapping
 export function useTypedSelector<T>(selector: (state: AppState) => T): T {
   return useSelector(selector);