update: graph implementation, filter in LL, eslit & prettier fix

Author: ashokdey

.eslintrc.json

@@ -3,6 +3,9 @@
     "node": true,
     "jest": true
   },
-  "extends": ["prettier", "airbnb-base"],
-  "plugins": ["prettier"]
+  "extends": ["airbnb", "plugin:prettier/recommended", "plugin:node/recommended"],
+  "plugins": ["prettier"],
+  "rules": {
+    "prettier/prettier": "error"
+  }
 }

.prettierrc.js

@@ -1,7 +1,8 @@
 module.exports = {
   semi: true,
-  trailingComma: "all",
+  trailingComma: 'all',
   singleQuote: true,
   printWidth: 120,
-  tabWidth: 2
+  tabWidth: 2,
+  arrowParens: 'always',
 };