Custom error message

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!

[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. 😃

[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!