useAway started

js/people.js

@@ -2,6 +2,7 @@ import Preact from "preact";
 import { html } from "htm";
 import { Consumer } from "./store.js";
 import * as Tree from "./tree.js";
+import React from "preact";
 
 /** @typedef {(e:SubmitEvent|Event)=>void|null} handler */
 
@@ -83,10 +84,17 @@ const PersonForm = () => {
 
 /** @type {()=>preact.VNode} */
 export default () => {
+  let [countGet, countSet] = Preact.useState(0);
+
+  let ref = Preact.useRef(null);
+  Tree.useAway(ref, () => {
+    countSet(countGet + 1);
+  });
+
   return html`
     <div>
-      <h2 class="pb-2 mb-2 border-b text-2xl font-sans border(">Person Records</h2>
-      <div class="px-2">
+      <h2 class="pb-2 mb-2 border-b text-2xl font-sans">Person Records ${countGet}</h2>
+      <div class="px-2" ref=${ref}>
         <${PersonForm}/>
         <${PersonTable}/>
 

js/tree.js

@@ -117,3 +117,23 @@ const Collapser = (inElement) => {
   };
   return show;
 };
+
+/** @typedef {(e:Event)=>void} Handler */
+/** @type {(inRef:React.MutableRefObject<HTMLElement|null>, inHandler:Handler)=>void} */
+export const useAway = (inRef, inHandler) => {
+  /** @type React.MutableRefObject<Handler> */
+  const handlerUser = React.useRef(inHandler);
+  handlerUser.current = inHandler;
+
+  /** @type React.MutableRefObject<Handler> */
+  const handlerClick = React.useRef((e) => {
+    const index = inRef.current ? e.composedPath().indexOf(inRef.current) : -1;
+    if (index < 0) {
+      handlerUser.current(e);
+    }
+  });
+  React.useEffect(() => {
+    document.addEventListener("click", handlerClick.current);
+    return () => document.removeEventListener("click", handlerClick.current);
+  }, []);
+};