我在验证 mongodb 中的字段时出错，nodejs

Question

These are the errors I got from backend while validating in model and received in 'err' variable. If I console.log(err), then it shows following errors.

Error [ValidationError]: employees validation failed: fullName: This field is required from model, email: This field is required from model
    at ValidationError.inspect (D:\Programming\MERN\CRUD\node_modules\mongoose\lib\error\validation.js:61:24)
    at formatValue (internal/util/inspect.js:703:31)
    at inspect (internal/util/inspect.js:272:10)
    at formatWithOptions (internal/util/inspect.js:1887:40)
    at Object.Console.<computed> (internal/console/constructor.js:284:10)
    at Object.log (internal/console/constructor.js:294:61)
    at handleValidationError (D:\Programming\MERN\CRUD\routes\/employeeRoute.js:46:13)
    at D:\Programming\MERN\CRUD\routes\/employeeRoute.js:33:17
    at D:\Programming\MERN\CRUD\node_modules\mongoose\lib\model.js:4915:16
    at D:\Programming\MERN\CRUD\node_modules\mongoose\lib\helpers\promiseOrCallback.js:16:11
    at D:\Programming\MERN\CRUD\node_modules\mongoose\lib\model.js:4938:21
    at D:\Programming\MERN\CRUD\node_modules\mongoose\lib\model.js:492:16
    at D:\Programming\MERN\CRUD\node_modules\kareem\index.js:246:48
    at next (D:\Programming\MERN\CRUD\node_modules\kareem\index.js:167:27)
    at next (D:\Programming\MERN\CRUD\node_modules\kareem\index.js:169:9)
    at Kareem.execPost (D:\Programming\MERN\CRUD\node_modules\kareem\index.js:217:3) {
  errors: {
    fullName: MongooseError [ValidatorError]: This field is required from model
        at new ValidatorError (D:\Programming\MERN\CRUD\node_modules\mongoose\lib\error\validator.js:29:11)
        at validate (D:\Programming\MERN\CRUD\node_modules\mongoose\lib\schematype.js:1178:13)
        at D:\Programming\MERN\CRUD\node_modules\mongoose\lib\schematype.js:1161:7
        at Array.forEach (<anonymous>)
        at SchemaString.SchemaType.doValidate (D:\Programming\MERN\CRUD\node_modules\mongoose\lib\schematype.js:1106:14)
        at D:\Programming\MERN\CRUD\node_modules\mongoose\lib\document.js:2378:18
        at processTicksAndRejections (internal/process/task_queues.js:79:11) {
      properties: [Object],
      kind: 'required',
      path: 'fullName',
      value: '',
      reason: undefined,
      [Symbol(mongoose:validatorError)]: true
    },
    email: MongooseError [ValidatorError]: This field is required from model
        at new ValidatorError (D:\Programming\MERN\CRUD\node_modules\mongoose\lib\error\validator.js:29:11)
        at validate (D:\Programming\MERN\CRUD\node_modules\mongoose\lib\schematype.js:1178:13)
        at D:\Programming\MERN\CRUD\node_modules\mongoose\lib\schematype.js:1161:7
        at Array.forEach (<anonymous>)
        at SchemaString.SchemaType.doValidate (D:\Programming\MERN\CRUD\node_modules\mongoose\lib\schematype.js:1106:14)
        at D:\Programming\MERN\CRUD\node_modules\mongoose\lib\document.js:2378:18
        at processTicksAndRejections (internal/process/task_queues.js:79:11) {
      properties: [Object],
      kind: 'required',
      path: 'email',
      value: '',
      reason: undefined,
      [Symbol(mongoose:validatorError)]: true
    }
  },
  _message: 'employees validation failed'
}

Now if I console.log('err.errors.fullName.message'). It works perfectly. But if there are more keys, it's obvious that we need to use loop. So if I try to iterate through keys of object as follow, then it throws following error.

for(field in err.errors){
.......
.......
}

Error is:

ReferenceError: field is not defined

What's the problem here?

Answer 1

First of all your backend should not give this type of error response as you mentioned in the above. This must be like a JSON response of errors. eg

{ success: false, errors: [{fullName: "fullName is required"}] }

Coming to your question. If you want to show error properly you can loop through the error which you can pic by the err.errors

eg err.errors.forEach(error => console.log(error) )

But again this is a very wrong way to throw the validation error. To validate any data you can use joi, request-validator, validatorjs, etc. Which will give you a perfect error response as you want? Why I am giving stress on this because you are exposing entire directory, files, model name, etc. I hope this may help you to solve your problem