Handling errors and avoiding duplicate category

server/controllers/category.js

@@ -1,5 +1,6 @@
 const Category = require("../models/categorySchema");
-const slugify = require("slugify")
+const slugify = require("slugify");
+const {errorHandler} = require("../helpers/databaseErrorHandler")
 
 exports.create = (req,res)=>{
     const {name} = req.body
@@ -10,7 +11,7 @@ exports.create = (req,res)=>{
     category.save((err,data)=>{
         if (err){
             return res.status(400).json({
-                error:err
+                error:errorHandler(err)
             })
         }
         res.json(data)

server/controllers/userAuthentication.js

@@ -82,7 +82,7 @@ exports.logout = (req,res)=>{
 
 exports.requireLogin = expressJwt({
     secret: process.env.JWT_TOKEN_SECRET,
-    algorithms: ['RS256'] 
+    algorithms: ['HS256'] 
 });
 
 

server/helpers/databaseErrorHandler.js

@@ -0,0 +1,39 @@
+'use strict';
+
+// Get unique error field name
+
+const uniqueMessage = error => {
+    let output;
+    try {
+        let fieldName = error.message.substring(error.message.lastIndexOf('.$') + 2, error.message.lastIndexOf('_1'));
+        output = fieldName.charAt(0).toUpperCase() + fieldName.slice(1) + ' already exists';
+    } catch (ex) {
+        output = 'Unique field already exists';
+    }
+
+    return output;
+};
+
+
+ // Get the error message from error object
+
+exports.errorHandler = error => {
+    let message = '';
+
+    if (error.code) {
+        switch (error.code) {
+            case 11000:
+            case 11001:
+                message = uniqueMessage(error);
+                break;
+            default:
+                message = 'Something went wrong';
+        }
+    } else {
+        for (let errorName in error.errorors) {
+            if (error.errorors[errorName].message) message = error.errorors[errorName].message;
+        }
+    }
+
+    return message;
+};