Custom error message

[jhnferraris]

Is it possible to modify the error object?

{
  "data": null,
  "errors": [
    {
      "message": "Insufficient Permissions.",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ],
      "path": [
        "getSurveys"
      ]
    }
  ]
}

Or can we directly use other error handler like apollo-errors instead of using the default "Insufficient permission"

Thanks for the assist!

[maticzav]

@jhnferraris custom errors are currently not supported, but I would love to hear more from you on this topic. Could you add this to roadmap thread? 🙂

#6

[dakshshah96]

@maticzav Any updates on this? I really want my developers to know what the cause of the error is. For example, JWT token has expired or something like Authorization header is required instead of just Insufficient Permissions..

[jhnferraris]

@dakshshah96

Since it is still in their roadmap, we opted on using a different approach. We used graphql-resolvers's, combineResolvers. In which we have one resolver doing the "validation" and throw custom error when the validation fails.

[dakshshah96]

@jhnferraris If it's not too much trouble, can you give me an example of how custom errors can be implemented? I've already defined all of my schema using graphql-tools in my apollo-server powered GraphQL backend. Thanks!

[jhnferraris]

@dakshshah96 Sure!

Example you have a "validation" resolver:

Resolver A: validateAuthObject

const { AuthorizationError } = require("../../errors"); // -- This is an instance of `apollo-errors`
module.exports = async (root, args, context, info) => {
  const user = _.get(args, "user", null);
  if (!user) {
    throw new AuthorizationError({
      message: "Missing user object.",
      data: {
        code: "auth-1"
      }
    });
  }
};

In your main resolver of a certain GraphQL query, let say getData(user: User, options: JSON!). We combine our validateUserObject and the "main" resolver.

const { combineResolvers } = require("graphql-resolvers");

getData: combineResolvers(validateUserObject, async (obj, args, context, info) => {
      const options = _.get(args, "options", {});
      return DataRepository.getAll(options);
    }),

Once user is null it will return t

{
  "data": null,
  "errors": [
    {
      "message": "Missing user object.",
      "name": "AuthorizationError",
      "time_thrown": "2018-03-22T10:48:42.113Z",
      "data": {
        "code": "auth-1"
      }
    }
  ]

}

Another approach is without the need for an extra resolver (if there's no need for reusability). Let's use your code here as an example:

const { UnknownError } = require('../../../helpers/errors')

const createAdmin = async (payload) => {
  try {
    const { error, value } = Joi.validate(payload, adminReqSchema)
    if (error) {
      throw new UnknownError({
        data: {
          reason: 'Schema validation error'
        }
      })
    }

    const admin = await new Admin({ name: value.name, phoneNumber: value.phoneNumber }).save()
    await new Auth({ userId: admin._id, role: 'admin', password: value.password }).save()

    return admin
  } catch (err) {
    
    console.log(err)
    throw err; // -- Re-throwing the error will allow GraphQL to immediately format the error as an `UnknownError` and will populate the `errors` field.
  }
}

I hope this helps. :)