From 762ac3a3f56e03bb0cb66f4de7378867adfe6a76 Mon Sep 17 00:00:00 2001
From: fantasticit <fantasticit@163.com>
Date: Mon, 25 Apr 2022 21:12:26 +0800
Subject: [PATCH] feat: use lru-cache in emoji-picker

---
 .../src/components/emoji-picker/index.tsx     |  20 +--
 packages/client/src/helpers/json.tsx          |   8 +
 packages/client/src/helpers/lru-cache.ts      | 149 ++++++++++++++++++
 3 files changed, 165 insertions(+), 12 deletions(-)
 create mode 100644 packages/client/src/helpers/lru-cache.ts

diff --git a/packages/client/src/components/emoji-picker/index.tsx b/packages/client/src/components/emoji-picker/index.tsx
index d0aad905..f2135546 100644
--- a/packages/client/src/components/emoji-picker/index.tsx
+++ b/packages/client/src/components/emoji-picker/index.tsx
@@ -1,12 +1,13 @@
 import React, { useCallback, useEffect, useMemo, useState } from 'react';
 import { Popover, Typography } from '@douyinfe/semi-ui';
 import { EXPRESSIONES, GESTURES, SYMBOLS, OBJECTS, ACTIVITIES, SKY_WEATHER } from './constants';
-import { setStorage, getStorage } from 'helpers/storage';
+import { createKeysLocalStorageLRUCache } from 'helpers/lru-cache';
 import { useToggle } from 'hooks/use-toggle';
 import styles from './index.module.scss';
 
 const { Title } = Typography;
-const RECENT_USED_EMOJI_KEY = 'RECENT_USED_EMOJI_KEY';
+
+const emojiLocalStorageLRUCache = createKeysLocalStorageLRUCache('EMOJI_PICKER', 20);
 
 const LIST = [
   {
@@ -49,22 +50,17 @@ export const EmojiPicker: React.FC<IProps> = ({ onSelectEmoji, children }) => {
 
   const selectEmoji = useCallback(
     (emoji) => {
-      setStorage(RECENT_USED_EMOJI_KEY, [...recentUsed, emoji].join('-'));
-      setRecentUsed((arr) => [...arr, emoji]);
+      emojiLocalStorageLRUCache.put(emoji);
+      setRecentUsed(emojiLocalStorageLRUCache.get() as string[]);
       onSelectEmoji && onSelectEmoji(emoji);
     },
-    [onSelectEmoji, recentUsed]
+    [onSelectEmoji]
   );
 
   useEffect(() => {
     if (!visible) return;
-    try {
-      const recentUsed = getStorage(RECENT_USED_EMOJI_KEY);
-      const toArr = recentUsed.split('-');
-      setRecentUsed(toArr);
-    } catch (e) {
-      //
-    }
+    emojiLocalStorageLRUCache.syncFromStorage();
+    setRecentUsed(emojiLocalStorageLRUCache.get() as string[]);
   }, [visible]);
 
   return (
diff --git a/packages/client/src/helpers/json.tsx b/packages/client/src/helpers/json.tsx
index ded039b4..665c7b36 100644
--- a/packages/client/src/helpers/json.tsx
+++ b/packages/client/src/helpers/json.tsx
@@ -5,3 +5,11 @@ export const safeJSONParse = (str, defaultValue = {}) => {
     return defaultValue;
   }
 };
+
+export const safeJSONStringify = (obj, defaultValue = '{}') => {
+  try {
+    return JSON.stringify(obj);
+  } catch (e) {
+    return defaultValue;
+  }
+};
diff --git a/packages/client/src/helpers/lru-cache.ts b/packages/client/src/helpers/lru-cache.ts
new file mode 100644
index 00000000..62fb33c0
--- /dev/null
+++ b/packages/client/src/helpers/lru-cache.ts
@@ -0,0 +1,149 @@
+import { safeJSONParse, safeJSONStringify } from './json';
+import { setStorage, getStorage } from './storage';
+
+class Node {
+  public key: string;
+  public value: string | number;
+  public prev: Node | null;
+  public next: Node | null;
+
+  constructor(key, value) {
+    this.key = key;
+    this.value = value;
+    this.prev = null;
+    this.next = null;
+  }
+}
+
+export class LRUCache {
+  private capacity: number;
+  private usedCapacity: number;
+  private head: Node;
+  private tail: Node;
+  private store: Record<string, Node>;
+
+  constructor(capacity) {
+    this.capacity = capacity || 20;
+    this.usedCapacity = 0;
+    this.store = {};
+    this.head = new Node('fakeHeadNode', 'fakeHeadNode');
+    this.tail = new Node('fakeTailNode', 'fakeTailNode');
+
+    this.head.next = this.tail;
+    this.tail.prev = this.head;
+  }
+
+  private removeNode(node) {
+    node.prev.next = node.next;
+    node.next.prev = node.prev;
+  }
+
+  private addToHead(node) {
+    node.prev = this.head;
+    node.next = this.head.next;
+    this.head.next.prev = node;
+    this.head.next = node;
+  }
+
+  private moveToHead(node) {
+    this.removeNode(node);
+    this.addToHead(node);
+  }
+
+  private removeTail() {
+    const node = this.tail.prev;
+    this.removeNode(node);
+    return node;
+  }
+
+  get(key) {
+    if (key in this.store) {
+      const node = this.store[key];
+      this.moveToHead(node);
+      return node.value;
+    }
+
+    return -1;
+  }
+
+  put(key, value) {
+    if (key in this.store) {
+      const node = this.store[key];
+      node.value = value;
+      this.moveToHead(node);
+    } else {
+      const node = new Node(key, value);
+      this.addToHead(node);
+      this.store[key] = node;
+      this.usedCapacity += 1;
+
+      if (this.usedCapacity > this.capacity) {
+        const tailNode = this.removeTail();
+        delete this.store[tailNode.key];
+        this.usedCapacity -= 1;
+      }
+    }
+  }
+
+  keys() {
+    const res = [];
+    let node = this.head;
+
+    while (node) {
+      res.push(node.key);
+      node = node.next;
+    }
+
+    return res.slice(1, -1);
+  }
+
+  values() {
+    const res = [];
+    let node = this.head;
+
+    while (node) {
+      res.push(node.value);
+      node = node.next;
+    }
+
+    return res.slice(1, -1);
+  }
+
+  toJSON() {
+    return this.store;
+  }
+}
+
+const USED_STORAGE_KEYS = [];
+
+export const createKeysLocalStorageLRUCache = (storageKey, capacity) => {
+  const lruCache = new LRUCache(capacity);
+
+  if (USED_STORAGE_KEYS.includes(storageKey)) {
+    throw new Error(`Storage Key ${storageKey} has been used!`);
+  }
+
+  USED_STORAGE_KEYS.push(storageKey);
+
+  return {
+    syncFromStorage() {
+      const data = getStorage(storageKey) || [];
+      data
+        .slice()
+        .reverse()
+        .forEach((key) => {
+          lruCache.put(key, key);
+        });
+    },
+    syncToStorage() {
+      setStorage(storageKey, safeJSONStringify(lruCache.keys()));
+    },
+    put(key) {
+      lruCache.put(key, key);
+      this.syncToStorage();
+    },
+    get(key?: string) {
+      return key ? lruCache.get(key) : lruCache.keys();
+    },
+  };
+};