feat: mark chat as unread (#475)

Co-authored-by: Pedro S. Lopez <pedroslopez@me.com>

src/Client.js

@@ -689,6 +689,17 @@ class Client extends EventEmitter {
         }, chatId);
     }
 
+    /**
+     * Mark the Chat as unread
+     * @param {string} chatId ID of the chat that will be marked as unread
+     */
+    async markChatUnread(chatId) {
+        await this.pupPage.evaluate(async chatId => {
+            let chat = await window.Store.Chat.get(chatId);
+            await window.Store.Cmd.markChatUnread(chat, true);
+        }, chatId);
+    }
+
     /**
      * Returns the contact ID's profile picture URL, if privacy settings allow it
      * @param {string} contactId the whatsapp user's ID

src/structures/Chat.js

@@ -161,6 +161,13 @@ class Chat extends Base {
         return this.client.unmuteChat(this.id._serialized);
     }
 
+    /**
+     * Mark this chat as unread
+     */
+    async markUnread(){
+        return this.client.markChatUnread(this.id._serialized);
+    }
+
     /**
      * Loads chat messages, sorted from earliest to latest.
      * @param {Object} searchOptions Options for searching messages. Right now only limit is supported.