Es6 escope start

.eslintrc.json

@@ -1,29 +1,3 @@
 {
-    "env": {
-        "browser": true,
-        "es6": true
-    },
-    "extends": "eslint:recommended",
-    "parserOptions": {
-        "sourceType": "module"
-    },
-    "rules": {
-        "no-console": 0,
-        "indent": [
-            "error",
-            2
-        ],
-        "linebreak-style": [
-            "error",
-            "unix"
-        ],
-        "quotes": [
-            "error",
-            "single"
-        ],
-        "semi": [
-            "error",
-            "always"
-        ]
-    }
+    "extends": "airbnb-base"
 }

image-message.model.js

@@ -0,0 +1,22 @@
+var Message = require('./message.model'); 
+
+class ImageMessage extends Message {
+  constructor(text = '', created = Date.now(),
+    url = '', thumbnail = '') {
+    super(text, created);
+    this.url = url;
+    this.thumbnail = thumbnail;
+  }
+
+  /**
+   * Method overriden
+   * @returns String
+   */
+  toString() {
+    return `Photo${super.toString()} ` +
+           `- Url: ${this.url} ` +
+           `- Thumbnail: ${this.thumbnail}`;
+  }
+}
+
+module.exports = ImageMessage;

index.js

@@ -0,0 +1,46 @@
+const Message = require('./message.model');
+const ImageMessage = require('./image-message.model');
+const fs = require('fs');
+const path = require('path');
+
+const emptyMessage = new Message();
+const emptyPhotoMessage = new ImageMessage();
+
+// console.log(emptyMessage);
+// console.log(emptyPhotoMessage);
+
+class MessagesService {
+  constructor() {
+    let resolvePromise;
+    let rejectPromise;
+    const filePath = path.join(__dirname, 'messages.json');
+    this.messagePromise = new Promise((resolve, reject) => {
+      resolvePromise = resolve;
+      rejectPromise = reject;
+    });
+    fs.readFile(filePath, { encoding: 'utf-8' }, (err, data) => {
+      if (err) {
+        rejectPromise(err);
+      } else {
+        const dataArray = JSON.parse(data);
+        const dataObj = dataArray.map(item =>
+          new Message(item.text, item.created));
+        resolvePromise(dataObj);
+      }
+    });
+  }
+
+  get messages() {
+    return this.messagePromise;
+  }
+}
+
+const messageService = new MessagesService();
+messageService.messages.then((messages) => {
+  for (let x = 0; x < messages.length; x++) {
+    console.log(String(messages[x]));
+  }
+  // console.log(messages);
+}).catch((err) => {
+  console.log(err);
+});

message.model.js

@@ -0,0 +1,27 @@
+class Message {
+  constructor(text = '', created = Date.now()) {
+    this.text = text;
+    this.created = created;
+  }
+  get created() {
+    return this._created;
+  }
+  set created(created) {
+    if (typeof created === 'undefined' || isNaN(created)) {
+      throw new Error('Invalid created');
+    }
+    if (Message.hasOwnProperty.call(this, '_created')) {
+      throw new Error('Created already defined');
+    }
+    this._created = created;
+  }
+  toString() {
+    const { created, text } = this;
+    return `Message created at: ${created} - Text: ${text}`;
+  }
+  static newEmptyMessage() {
+    return new Message();
+  }
+}
+
+module.exports = Message;

messages-generator.js

@@ -0,0 +1,9 @@
+console.log('[');
+for (let x = 0; x < 50; x += 1) {
+  console.log(
+  `  {
+    "text": "Message ${x + 1}",
+    "created": ${Date.now() - parseInt(Math.random() * 20000, 10)}` +
+  '\n  },');
+}
+console.log(']');

messages.json

@@ -0,0 +1,202 @@
+[
+  {
+    "text": "Message 1",
+    "created": 1485580795316
+  },
+  {
+    "text": "Message 2",
+    "created": 1485580806337
+  },
+  {
+    "text": "Message 3",
+    "created": 1485580806916
+  },
+  {
+    "text": "Message 4",
+    "created": 1485580800756
+  },
+  {
+    "text": "Message 5",
+    "created": 1485580808356
+  },
+  {
+    "text": "Message 6",
+    "created": 1485580807654
+  },
+  {
+    "text": "Message 7",
+    "created": 1485580806217
+  },
+  {
+    "text": "Message 8",
+    "created": 1485580812551
+  },
+  {
+    "text": "Message 9",
+    "created": 1485580798307
+  },
+  {
+    "text": "Message 10",
+    "created": 1485580811762
+  },
+  {
+    "text": "Message 11",
+    "created": 1485580797617
+  },
+  {
+    "text": "Message 12",
+    "created": 1485580796283
+  },
+  {
+    "text": "Message 13",
+    "created": 1485580808593
+  },
+  {
+    "text": "Message 14",
+    "created": 1485580804604
+  },
+  {
+    "text": "Message 15",
+    "created": 1485580805217
+  },
+  {
+    "text": "Message 16",
+    "created": 1485580812013
+  },
+  {
+    "text": "Message 17",
+    "created": 1485580801476
+  },
+  {
+    "text": "Message 18",
+    "created": 1485580796691
+  },
+  {
+    "text": "Message 19",
+    "created": 1485580809150
+  },
+  {
+    "text": "Message 20",
+    "created": 1485580809749
+  },
+  {
+    "text": "Message 21",
+    "created": 1485580798689
+  },
+  {
+    "text": "Message 22",
+    "created": 1485580813533
+  },
+  {
+    "text": "Message 23",
+    "created": 1485580809304
+  },
+  {
+    "text": "Message 24",
+    "created": 1485580800410
+  },
+  {
+    "text": "Message 25",
+    "created": 1485580813492
+  },
+  {
+    "text": "Message 26",
+    "created": 1485580804881
+  },
+  {
+    "text": "Message 27",
+    "created": 1485580807428
+  },
+  {
+    "text": "Message 28",
+    "created": 1485580799216
+  },
+  {
+    "text": "Message 29",
+    "created": 1485580806498
+  },
+  {
+    "text": "Message 30",
+    "created": 1485580807991
+  },
+  {
+    "text": "Message 31",
+    "created": 1485580809480
+  },
+  {
+    "text": "Message 32",
+    "created": 1485580813968
+  },
+  {
+    "text": "Message 33",
+    "created": 1485580797256
+  },
+  {
+    "text": "Message 34",
+    "created": 1485580803548
+  },
+  {
+    "text": "Message 35",
+    "created": 1485580814760
+  },
+  {
+    "text": "Message 36",
+    "created": 1485580796059
+  },
+  {
+    "text": "Message 37",
+    "created": 1485580813855
+  },
+  {
+    "text": "Message 38",
+    "created": 1485580802752
+  },
+  {
+    "text": "Message 39",
+    "created": 1485580805371
+  },
+  {
+    "text": "Message 40",
+    "created": 1485580795256
+  },
+  {
+    "text": "Message 41",
+    "created": 1485580811512
+  },
+  {
+    "text": "Message 42",
+    "created": 1485580813071
+  },
+  {
+    "text": "Message 43",
+    "created": 1485580814474
+  },
+  {
+    "text": "Message 44",
+    "created": 1485580798669
+  },
+  {
+    "text": "Message 45",
+    "created": 1485580803371
+  },
+  {
+    "text": "Message 46",
+    "created": 1485580801132
+  },
+  {
+    "text": "Message 47",
+    "created": 1485580799789
+  },
+  {
+    "text": "Message 48",
+    "created": 1485580811027
+  },
+  {
+    "text": "Message 49",
+    "created": 1485580814344
+  },
+  {
+    "text": "Message 50",
+    "created": 1485580804181
+  }
+]