From ab1fe668b4fb37fc3dac349c39e39d50d9f8f80a Mon Sep 17 00:00:00 2001
From: mitsuha <mitsuhatu@gmail.com>
Date: Wed, 24 Aug 2022 01:54:10 +0800
Subject: [PATCH] opti: 1.adjust eventlistener;

---
 .../workspace/docs/components/toc/TOC.tsx     | 20 ++++++++++---
 .../src/pages/workspace/docs/utils/toc.ts     | 30 ++++++++++++-------
 2 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/apps/ligo-virgo/src/pages/workspace/docs/components/toc/TOC.tsx b/apps/ligo-virgo/src/pages/workspace/docs/components/toc/TOC.tsx
index be567780f7..dd12469d90 100644
--- a/apps/ligo-virgo/src/pages/workspace/docs/components/toc/TOC.tsx
+++ b/apps/ligo-virgo/src/pages/workspace/docs/components/toc/TOC.tsx
@@ -14,6 +14,7 @@ import {
     destroyEventList,
     getContentByAsyncBlocks,
     getPageTOC,
+    listenerMap,
     type TocType,
 } from '../../utils/toc';
 
@@ -123,24 +124,35 @@ export const Toc = (props: Props) => {
     const { page_id } = useParams();
     const [tocDataSource, setTocDataSource] = useState<TocType[]>([]);
     const [activeBlockId, setActiveBlockId] = useState('');
-    const [blockEventListeners, setBlockEventListeners] = useState([]);
 
     const updateTocDataSource = useCallback(async () => {
-        destroyEventList(blockEventListeners);
+        /* page listener: trigger update-notice when add new group */
+        const pageAsyncBlock = (await editor.getBlockByIds([page_id]))?.[0];
+        if (!listenerMap.has(pageAsyncBlock.id)) {
+            listenerMap.set(
+                pageAsyncBlock.id,
+                pageAsyncBlock.onUpdate(updateTocDataSource)
+            );
+        }
 
+        /* block listener: trigger update-notice when change block content */
         const { children = [] } =
             (await editor.queryByPageId(page_id))?.[0] || {};
         const asyncBlocks = (await editor.getBlockByIds(children)) || [];
-        const { tocContents, eventListeners } = await getContentByAsyncBlocks(
+        const { tocContents } = await getContentByAsyncBlocks(
             asyncBlocks,
             updateTocDataSource
         );
 
+        /* toc: flat content */
         const tocDataSource = getPageTOC(asyncBlocks, tocContents);
         setTocDataSource(tocDataSource);
-        setBlockEventListeners(eventListeners);
+
+        /* remove listener when unmount component */
+        return destroyEventList;
     }, [editor, page_id]);
 
+    /* init toc and add page/block update-listener & unmount-listener */
     useEffect(() => {
         (async () => {
             await updateTocDataSource();
diff --git a/apps/ligo-virgo/src/pages/workspace/docs/utils/toc.ts b/apps/ligo-virgo/src/pages/workspace/docs/utils/toc.ts
index 2ef9a39032..b9a6e5dd56 100644
--- a/apps/ligo-virgo/src/pages/workspace/docs/utils/toc.ts
+++ b/apps/ligo-virgo/src/pages/workspace/docs/utils/toc.ts
@@ -13,16 +13,16 @@ export const BLOCK_TYPES = {
     HEADING3: 'heading3',
 };
 
+/* store page/block unmount-listener */
+export const listenerMap = new Map<string, () => void>();
+
 /* 😞😞sorry, I don't know how to define unlimited dimensions array */
 const getContentByAsyncBlocks = async (
     asyncBlocks: AsyncBlock[] = [],
     callback: () => void
 ): Promise<{
     tocContents: any[];
-    eventListeners: (() => void | undefined)[];
 }> => {
-    const eventListeners = [];
-
     const collect = async (asyncBlocks): Promise<any[]> => {
         /* maybe should recast it to tail recursion */
         return await Promise.all(
@@ -33,11 +33,14 @@ const getContentByAsyncBlocks = async (
                     return collect(asyncBlocks);
                 }
 
-                /* get update notice */
-                const destroyHandler = asyncBlock.onUpdate(callback);
+                /* add only once event listener for every block */
+                if (!listenerMap.has(asyncBlock.id)) {
+                    /* get update notice */
+                    const destroyHandler = asyncBlock.onUpdate(callback);
 
-                /* collect destroy handlers */
-                eventListeners.push(destroyHandler);
+                    /* collect destroy handlers */
+                    listenerMap.set(asyncBlock.id, destroyHandler);
+                }
 
                 const { id, type } = asyncBlock;
                 if (Object.values(BLOCK_TYPES).includes(type)) {
@@ -57,10 +60,14 @@ const getContentByAsyncBlocks = async (
 
     return {
         tocContents: await collect(asyncBlocks),
-        eventListeners,
     };
 };
 
+/**
+ * get flat toc
+ * @param asyncBlocks
+ * @param tocContents
+ */
 const getPageTOC = (asyncBlocks: AsyncBlock[], tocContents): TocType[] => {
     return tocContents
         .reduce((tocGroupContent, tocContent, index) => {
@@ -83,9 +90,10 @@ const getPageTOC = (asyncBlocks: AsyncBlock[], tocContents): TocType[] => {
         .filter(Boolean);
 };
 
-const destroyEventList = (
-    eventListeners: (() => void | undefined)[] = []
-): boolean => {
+/* destroy page/block update-listener */
+const destroyEventList = (): boolean => {
+    const eventListeners = listenerMap.values();
+
     for (const eventListener of eventListeners) {
         eventListener?.();
     }