Refactor api.send Message related logic into a separate private method

src/types/Base.js

@@ -1,7 +1,6 @@
 import { EventEmitter } from 'events';
 
 const ANSWER_THRESHOLD = 10;
-const MSG_MAX_LENGTH = 4096;
 
 /**
  * Base class of all classes
@@ -36,25 +35,12 @@ export default class Base extends EventEmitter {
 
     let messageId;
     return new Promise((resolve, reject) => {
-      let promiseChain;
+      this._apiSend(bot)
-
+        .then(response => {
-      if (this.method === 'sendMessage' && this.properties.text.length > MSG_MAX_LENGTH) {
+          messageId = response.result.message_id;
-        promiseChain = Promise.resolve();
+          this.emit('message:sent', response);
-        const textChunks = this.properties.text.match(new RegExp(`.{1,${MSG_MAX_LENGTH}}`, 'g'));
+        })
-
+        .catch(reject);
-        textChunks.forEach(chunk => {
-          const properties = Object.assign({}, this.properties, { text: chunk });
-          delete properties.parse_mode; // any unclosed tags, text modifiers will not send out, send as pure text
-          promiseChain = promiseChain.then(() => bot.api[this.method](properties));
-        });
-      } else {
-        promiseChain = bot.api[this.method](this.properties);
-      }
-
-      promiseChain.then(response => {
-        messageId = response.result.message_id;
-        this.emit('message:sent', response);
-      }).catch(reject);
 
       if (this._keyboard.one_time_keyboard) {
         this._keyboard.replyMarkup = '';
@@ -62,6 +48,7 @@ export default class Base extends EventEmitter {
 
       const chat = this.properties.chat_id;
       let answers = 0;
+
       bot.on('update', function listener(result) {
         answers += result.length;
 
@@ -69,8 +56,8 @@ export default class Base extends EventEmitter {
           // if in a group, there will be a reply to this message
           if (chat < 0) {
             return message.chat.id === chat
-                   && message.reply_to_message
+              && message.reply_to_message
-                   && message.reply_to_message.message_id === messageId;
+              && message.reply_to_message.message_id === messageId;
           }
 
           return message && message.chat.id === chat;
@@ -78,9 +65,7 @@ export default class Base extends EventEmitter {
 
         if (update) {
           resolve(update.message);
-
           this.emit('message:answer', update.message);
-
           bot.removeListener('update', listener);
         }
 
@@ -91,6 +76,10 @@ export default class Base extends EventEmitter {
     });
   }
 
+  _apiSend(bot) {
+    return bot.api[this.method](this.properties);
+  }
+
   /**
    * Returns properties of the object
    * @return {object} properties of object

src/types/Message.js

@@ -1,5 +1,18 @@
 import Base from './Base';
 
+const MSG_MAX_LENGTH = 4096;
+
+function splitToChunks(str, size) {
+  const numChunks = Math.ceil(str.length / size);
+  const chunks = new Array(numChunks);
+
+  for (let i = 0, o = 0; i < numChunks; ++i, o += size) {
+    chunks[i] = str.substr(o, size);
+  }
+
+  return chunks;
+}
+
 /**
  * Message class, used to send message to a chat
  */
@@ -93,5 +106,25 @@ export default class Message extends Base {
     return this;
   }
 
+  // override Base.prototype._apiSend() method
+  _apiSend(bot) {
+    if (this.properties.text && this.properties.text.length > MSG_MAX_LENGTH) {
+      let promiseChain = Promise.resolve();
+      const textChunks = splitToChunks(this.properties.text, MSG_MAX_LENGTH);
+
+      textChunks.forEach(chunk => {
+        const properties = Object.assign({}, this.properties, { text: chunk });
+        // any unclosed tags, text modifiers will not send out, send as pure text
+        delete properties.parse_mode;
+
+        promiseChain = promiseChain.then(() => bot.api[this.method](properties));
+      });
+
+      return promiseChain;
+    }
+
+    return bot.api[this.method](this.properties);
+  }
+
   // This class inherits Base's send method
 }