How to approach a GraphQL query that returns a boolean value?

Question

Need to check whether an email is available or taken during the user sign-up process. The goal is to quickly query, using GraphQL, the API server and have it tell us if the email is available or taken.

What is the general best practice on a simple boolean-ish type of situation using GraphQL?

Below is what I have come up with but I am unsure if this is a good practice or not and want to hear feedback on a better practice on queries like this.

Request:

query {
  emailExists(email:"jane@doe.com") {
    is
  }
}

Response:

{
  "data": {
    "emailExists": {
      "is": true
    }
  }
}

score 30 · Accepted Answer · answered Jul 04 '19 at 00:43

30

A "query" is just a field on what happens to be the Query type. A field can return any output type, including scalars -- it doesn't need to return an object. So it's sufficient to have a schema like:

type Query {
  emailExists(email: String!): Boolean!
}

The only reason to prefer an object type would be if you anticipated wanting to add additional fields in the future (i.e. something other than your current is field).

answered Jul 04 '19 at 00:43

Daniel Rearden

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183

Exactly what I am looking for!! Thanks so much. – Chad Taylor Jul 04 '19 at 01:35
14

Just for the records, with this solution the request would be this (no field selection is needed): ```graphql query { emailExists(email:"jane@doe.com") } ``` – Marco Mar 11 '20 at 10:03
1

@Marco eslint crashes if i use a query without selection – Moritz Roessler May 29 '22 at 16:49

How to approach a GraphQL query that returns a boolean value?

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