Add eslint and give it airbnb configuration

.eslintignore

@@ -0,0 +1 @@
+node_modules

.eslintrc.json

@@ -0,0 +1,13 @@
+{
+    "env": {
+        "node": true
+    },
+    "extends": [
+        "airbnb-base"
+    ],
+    "parserOptions": {
+        "ecmaVersion": 2018
+    },
+    "rules": {
+    }
+}

package.json

@@ -10,12 +10,17 @@
   },
   "scripts": {
     "start": "node src/index.js",
-    "dev": "nodemon src/index.js"
+    "dev": "nodemon src/index.js",
+    "lint": "eslint .",
+    "lint:fix": "eslint . --fix"
   },
   "dependencies": {
     "express": "^4.17.1"
   },
   "devDependencies": {
+    "eslint": "^6.6.0",
+    "eslint-config-airbnb-base": "^14.0.0",
+    "eslint-plugin-import": "^2.18.2",
     "nodemon": "^1.19.4"
   }
 }

src/app.js

@@ -1,8 +1,8 @@
 const express = require('express');
 
-const app = new express();
+const app = express();
 app.use('/', (req, res) => {
-  res.send("Working");
+  res.send('Working');
 });
 
 module.exports = app;

src/index.js

@@ -1,4 +1,4 @@
-const app = require("./app");
+const app = require('./app');
 
 const port = 3000;
 app.listen(port, () => {