graphql-operation-to-pojo

graphql-operation-to-pojo

Converts GraphQL operations to plain old JS objects (POJOs), ready to to be serialized to JSON.

This can be used to parse the info argument (GraphQLResolveInfo) passed to GraphQL resolvers.

Installation

npm i -S graphql-operation-to-pojo

Or:

yarn add graphql-operation-to-pojo

Usage

myResolver(obj, args, context, info) {
    const queryPOJO = graphqlOperationToPOJO(info)
    ...
}

There is also a helper function to serialize the result to a JSON string:

const jsonString = graphqlOperationToJSON(info)

(This is equivalent to calling JSON.stringify(graphqlOperationToPOJO(info)))

Options

Options can optionally be passed as a second argument, e.g.:

graphqlOperationToPOJO(info, {
    includeFieldPath: true,
    includeReturnType: true,
})

Available options:

• includeFieldPath: boolean (defaults to false)

  If true, a path property will be added to each field object and set to the path to the field from the root of the query, e.g. 'hero.name'

• includeReturnTypes: boolean (defaults to false)

  If true, the return type of each field will be included in the result.

Tip: When using includeReturnTypes, you can use getNamedType() from graphql.js to strip any wrapping non-null or list types and get the underlying type. For example:

import { getNamedType } from 'graphql'
...
/*
Suppose we're running a query that returns a list of users:

  type Query {
    users: [User!]!
  }
*/
const returnType = getNamedType(queryPojo.fields[0].returnType)
console.log(returnType.toString())
// Output: 'User'

Examples

Given the query:

query {
    hero(episode: NEWHOPE) {
        name
        friends {
            name
            appearsIn
        }
    }
}

graphqlOperationToPOJO will return:

{
    "operation": "query",
    "fields": [
        {
            "name": "hero",
            "fields": [
                {
                    "name": "name"
                },
                {
                    "name": "friends",
                    "fields": [
                        {
                            "name": "name"
                        },
                        {
                            "name": "appearsIn"
                        }
                    ]
                }
            ],
            "arguments": {
                "episode": "NEWHOPE"
            }
        }
    ]
}

Aliases

If the query contains aliases, the field object will include an alias property, e.g.:

{
    hero(episode: NEWHOPE) {
        heroName: name
    }
}

{
    "operation": "query",
    "fields": [
        {
            "name": "hero",
            "fields": [
                {
                    "name": "name",
                    "alias": "heroName"
                }
            ],
            "arguments": {
                "episode": "NEWHOPE"
            }
        }
    ]
}

Fragments

Type conditions for fragments are stored in a fragmentType property, e.g.:

{
    character(id: "1000") {
        ... on Human {
            id
            name
            friends {
                id
            }
        }
        ... on Droid {
            name
            friends {
                name
            }
        }
    }
}

{
    "operation": "query",
    "fields": [
        {
            "name": "character",
            "fields": [
                {
                    "name": "id",
                    "fragmentType": "Human"
                },
                {
                    "name": "name",
                    "fragmentType": "Human"
                },
                {
                    "name": "friends",
                    "fragmentType": "Human",
                    "fields": [
                        {
                            "name": "id"
                        }
                    ]
                },
                {
                    "name": "name",
                    "fragmentType": "Droid"
                },
                {
                    "name": "friends",
                    "fragmentType": "Droid",
                    "fields": [
                        {
                            "name": "name"
                        }
                    ]
                }
            ],
            "arguments": {
                "id": "1000"
            }
        }
    ]
}