refactor: convert errors.server.controller to typescript utility func…

…tion (#602)

* chore: rename errors server controller to typescript

* chore: add @types/mongodb as devdependency

* chore: define MongoError interface

* chore: typescripify errors server controller

* chore: rename errors server controller spec to ts

* chore: clean up errors.server.controller.spec.ts

* refactor: use destructuring assignment for isEmpty

* chore: remove types from JSDocs

* chore: remove defaultErrorMessage from exports

* chore: remove mongoDuplicateKeyError as only UserSchema has unique key and that is already validated

* refactor: use arrow function for getMongoErrorMessage

* refactor: clean up getMongoErrorMessage

* chore: shift errors.server.controller to utility function

* chore: update tests

* chore: shift defaultErrorMessage to function parameter

package.json

@@ -182,6 +182,7 @@
     "@types/ip": "^1.1.0",
     "@types/jest": "^26.0.15",
     "@types/json-stringify-safe": "^5.0.0",
+    "@types/mongodb": "^3.5.27",
     "@types/mongodb-uri": "^0.9.0",
     "@types/mongoose": "^5.7.36",
     "@types/node": "^14.14.7",

src/app/controllers/admin-forms.server.controller.js

@@ -10,7 +10,7 @@ const JSONStream = require('JSONStream')
 const { StatusCodes } = require('http-status-codes')
 
 const logger = require('../../config/logger').createLoggerWithLabel(module)
-const errorHandler = require('./errors.server.controller')
+const errorHandler = require('../utils/handle-mongo-error')
 const { createReqMeta } = require('../utils/request')
 const { FormLogoState } = require('../../types')
 

src/app/controllers/encrypt-submissions.server.controller.js

@@ -5,7 +5,7 @@ const JSONStream = require('JSONStream')
 const { StatusCodes } = require('http-status-codes')
 
 const mongoose = require('mongoose')
-const errorHandler = require('./errors.server.controller')
+const errorHandler = require('../utils/handle-mongo-error')
 const {
   getEncryptSubmissionModel,
 } = require('../models/submission.server.model')

src/app/controllers/submissions.server.controller.js

@@ -3,7 +3,7 @@
 const axios = require('axios')
 
 const mongoose = require('mongoose')
-const errorHandler = require('./errors.server.controller')
+const errorHandler = require('../utils/handle-mongo-error')
 const getSubmissionModel = require('../models/submission.server.model').default
 const Submission = getSubmissionModel(mongoose)
 

src/app/utils/handle-mongo-error.ts

@@ -0,0 +1,38 @@
+import { MongoError } from 'mongodb'
+import { Error as MongooseError } from 'mongoose'
+
+export const getMongoErrorMessage = (
+  err?: MongoError | MongooseError | string,
+  // Default error message if no more specific error
+  defaultErrorMessage = 'An unexpected error happened. Please try again.',
+): string => {
+  if (!err) {
+    return ''
+  }
+
+  // Handle base Mongo engine errors
+  if (err instanceof MongoError) {
+    switch (err.code) {
+      case 10334: // BSONObj size invalid error
+        return 'Your form is too large to be supported by the system.'
+      default:
+        return defaultErrorMessage
+    }
+  }
+
+  // Handle mongoose errors
+  if (err instanceof MongooseError.ValidationError) {
+    // Join all error messages into a single message if available.
+    const joinedMessage = Object.values(err.errors)
+      .map((err) => err.message)
+      .join(', ')
+
+    return joinedMessage ?? err.message ?? defaultErrorMessage
+  }
+
+  if (err instanceof MongooseError) {
+    return err.message ?? defaultErrorMessage
+  }
+
+  return err ?? defaultErrorMessage
+}

tests/unit/backend/utils/handle-mongo-error.spec.ts

@@ -0,0 +1,51 @@
+import { MongoError } from 'mongodb'
+import { Error as MongooseError } from 'mongoose'
+
+import { getMongoErrorMessage } from 'src/app/utils/handle-mongo-error'
+
+describe('handleMongoError', () => {
+  describe('getMongoErrorMessage', () => {
+    it('should return blank string if no error', () => {
+      expect(getMongoErrorMessage()).toEqual('')
+    })
+
+    it('should return string if error is string', () => {
+      const err = 'something failed'
+      expect(getMongoErrorMessage(err)).toEqual(err)
+    })
+
+    it('should return form too large error message for error code 10334', () => {
+      const err = new MongoError('MongoError')
+      err.code = 10334
+
+      expect(getMongoErrorMessage(err)).toEqual(
+        'Your form is too large to be supported by the system.',
+      )
+    })
+
+    it('should return default error message for other MongoError error code', () => {
+      const err = new MongoError('MongoError')
+      expect(getMongoErrorMessage(err)).toEqual(
+        'An unexpected error happened. Please try again.',
+      ) // Preset default error message
+      expect(getMongoErrorMessage(err, 'new error message')).toEqual(
+        'new error message',
+      ) // Changed default error message
+    })
+
+    it('should join all error messages into a single message if available.', () => {
+      const err = new MongooseError.ValidationError()
+      const err1 = new MongooseError.ValidatorError({})
+      err1.message = 'abc'
+      const err2 = new MongooseError.ValidatorError({})
+      err2.message = 'def'
+      err.errors = { err1, err2 }
+      expect(getMongoErrorMessage(err)).toEqual('abc, def')
+    })
+
+    it('should return error message for MongooseError', () => {
+      const err = new MongooseError('mongooseError')
+      expect(getMongoErrorMessage(err)).toEqual('mongooseError')
+    })
+  })
+})