无法在类型 \\"Mutation\\" 上查询字段 \\"addWorkout\\"

Question

I am fairly new to GraphQL, my previous question was regarding some reference error I was getting which I eventually resolved, however, now I am getting this error. It seems that I cannot add a workout as it doesn't recognize that it is a mutation field within the schema.

I keep getting the error of

Cannot query field \"addWorkout\" on type \"Mutation\

Anyway, on app.js, this is my code

const express = require("express")
const app = express();
const userSchema = require("./graph-schema/userQueries")
const workoutSchema = require("./graph-schema/workoutQueries")
const mealSchema = require("./graph-schema/mealQueries")
const mongoose = require("mongoose")
const {mergeSchemas} = require("graphql-tools")

//connect to mongoDB atlase database
mongoose.connect("mongodb+srv://Zubair97:superman2008@cluster0-epauj.mongodb.net/test?retryWrites=true&w=majority")
mongoose.connection.once("open", () => {
    console.log("Connected to database")
})

const combinedSchemas = mergeSchemas({
    schemas: [
        userSchema,
        mealSchema,
        workoutSchema
    ],
})




//this module allows express to communicate with graphql ;
//we use it as a single endpoint
const graphqlHTTP = require("express-graphql")

app.use("/graphql" , graphqlHTTP({
    schema: combinedSchemas,
    graphiql: true


}))


app.listen(4000, () => {
    console.log(`Listening on port 4000`)
})

The workout queries and mutations are defined in a file called workoutQueries.js, which I have exported, you can see that I have addWorkout defined in the resolvers

const graphql = require("graphql")
const {WorkoutType} = require("./schema")
const Workout = require("../models/Workout.js")
const {GraphQLObjectType, GraphQLID, GraphQLString, GraphQLSchema, GraphQLInt, GraphQLList} = graphql;

const WorkoutQuery = new GraphQLObjectType({
    name: "WorkoutQuery",
    fields: () => ({
        workout: {
            type: WorkoutType,
            args: {id: {type: GraphQLID}},
            resolve(parent, args){
                //returns the workout instance from the database
                return Workout.findById(args.id)
            }

        },

        workouts: {
            type: new GraphQLList(WorkoutType),
            resolve(parent, args){
                //returns all workouts from the databse
                return Workout.find({})
            }
        }
    })

})

const WorkoutMutation = new GraphQLObjectType({
    name: "WorkoutMutation",
    addWorkout: {
        type: WorkoutType,
        args: {
            name: {type: GraphQLString},
            reps: {type: GraphQLInt},
            sets: {type: GraphQLInt},
            burnedCalories: {type: GraphQLInt},
            userId: {type: GraphQLID},

        },
        resolve(parent, args){
            let workout = new Workout({
                name: args.name,
                reps: args.reps,
                sets: args.sets,
                burnedCalories: args.burnedCalories,
                userId: args.userId
            })

            return workout.save();
        }
    },

})

module.exports = new GraphQLSchema({
    query: WorkoutQuery,
    mutation: WorkoutMutation
})

Also, this issue is occurring even if I try to add a meal, the queries and mutations are defined at a file called mealQueries.js, which I have exported

const graphql = require("graphql")
const {MealType, NutritionType} = require("./schema")
const Meal = require("../models/Meal.js")
const {GraphQLObjectType, GraphQLID, GraphQLString, GraphQLSchema, GraphQLInt, GraphQLList} = graphql;

const MealQuery = new GraphQLObjectType({
    name: "MealQueries",
    fields: () => ({
        meal: {
            type: MealType,
            args: {id: {type: GraphQLID}},
            resolve(parent, args){
                return Meal.findById(args.id)
            }
        },

        meals: {
            type: new GraphQLList(MealType),
            resolve(parent, args){
                return Meal.find({})
            }
        }

    })

})

const MealMutation = new GraphQLObjectType({
    name: "MealMutation",
    addMeal: {
        type: MealType,
        args: {
            name: {type: GraphQLString},
            servings: {type: GraphQLInt},
            calories: {type: GraphQLInt},
            nutrition: {type: NutritionType},
            userId: {type: GraphQLID}
        },
        resolve(parent, args){

            let meal = new Meal({
                userId: args.userId,
                name: args.name,
                servings: args.servings,
                calories: args.calories,
                nutrition: {
                    carbohydrates: args.nutrition.carbohydrates,
                    fats: args.nutrition.fats,
                    proteins: args.nutrition.proteins
                }
            })

            return meal.save();
        }
    }

})

module.exports = new GraphQLSchema({
    query: MealQuery,
    mutation: MealMutation
})

I have no issue in creating a user and authenticating a user, the queries and mutation for that are defined in userQueries.js

const graphql = require("graphql")
const User = require("../models/User.js")
const bcrypt = require("bcrypt")
const jwt = require("jsonwebtoken")
const {AuthType, UserType} = require("./schema")
const {GraphQLObjectType, GraphQLID, GraphQLString, GraphQLSchema, GraphQLInt, GraphQLList} = graphql;


const UserQuery = new GraphQLObjectType({
    name: "UserQuery",
    fields: () => ({
        user: {
            type: UserType,
            args: {id: {type: GraphQLID}},
            resolve(parent, args){
                //returns the user from the database
                return User.findById(args.id)
            }
        },
        login: {
            type: AuthType,
            args: {email: {type: GraphQLString}, password: {type: GraphQLString}},
            resolve(parent, {email, password}){
                return User.findOne({email: email}).then((user) => {
                    const isEqual = bcrypt.compare(password, user.password)
                    if (!isEqual) {
                        throw new Error('Password is incorrect!');
                    }

                    const token = jwt.sign({
                        userId: user.id,
                        email: user.email},
                        "a_super_secret",
                        {expiresIn: "1h"}
                    )

                    return {token: token, userId: user.id}


                })

            }
        }


    })


})



const UserMutation = new GraphQLObjectType({
    name: "Mutation",
    fields: {
        addUser: {
            type: UserType,
            args: {
                name: {type: GraphQLString},
                email: {type: GraphQLString},
                password: {type: GraphQLString}
            },
            async resolve(parent, args){
                const existingUser =  await User.findOne({email: args.email})
                if (!existingUser){
                    const error = new Error("User already exists");
                }

                const encryptedPassword =  await bcrypt.hash(args.password, 12)

                let user = new User({
                    name: args.name,
                    email: args.email,
                    password: encryptedPassword
                })

                const createdUser =  user.save();
                return createdUser
            }
        }



    }
})


module.exports = new GraphQLSchema({
    query: UserQuery,
    mutation: UserMutation,
})

I have also defined the UserType, AuthType, MealType, NutritionType and WorkoutType in a file called schema.js

const graphql = require("graphql")
const Workout = require("../models/Workout.js")
const User = require("../models/User.js")
const Meal = require("../models/Meal")

const {GraphQLObjectType, GraphQLID, GraphQLString, GraphQLSchema, GraphQLInt, GraphQLList} = graphql;

//describes what attributes and its types, a User has in each query
const UserType = new GraphQLObjectType({
    name: "User",
    fields: () => ({
        id: {type: GraphQLID},
        name: {type: GraphQLString},
        email: {type: GraphQLString},
        password: {type: GraphQLString},
        workouts: {
            type: new GraphQLList(WorkoutType),
            resolve(parent, args){
                //returns all the workouts created by a user
                return Workout.findById({userId: parent.id})
            }
        },
        meals: {
            type: new GraphQLList(MealType),
            resolve(parent, args){
                //returns all the meals created by a user
                return Meal.findById({userId: parent.id})
            }
        }

    })
})

const NutritionType = new GraphQLObjectType({
    name: "Nutrition",
    fields: () => ({
        carbohydrates: {type: GraphQLInt},
        fats: {type: GraphQLInt},
        proteins: {type: GraphQLInt}
    })
})



const WorkoutType = new GraphQLObjectType({
    name: "Workout",
    fields: () => ({
        id: {type: GraphQLID},
        name: {type: GraphQLString},
        reps: {type: GraphQLInt},
        burnedCalories: {type: GraphQLInt},
        sets: {type: GraphQLInt},
        user: {
            type: UserType,
            resolve(parent, args){
                //returns the user from the database that created the workout instance
                return User.findById(parent.userId)

            }
        }

    })
})




const AuthType = new GraphQLObjectType({
    name: "Authentication",
    fields: () => ({
        token: {type: GraphQLString},
        userId: {type: GraphQLString}
    })
})



const MealType = new GraphQLObjectType({
    name: "Meal",
    fields: () => ({
        id: {type: GraphQLID},
        calories: {type: GraphQLInt},
        servings: {type: GraphQLInt},
        nutrition: {type: NutritionType},
        user: {
            type: UserType,
            resolve(parent, args){
                //returns the user from the database that created the meal instance
                return User.findById(parent.userId)
            }
        }

    })
})




module.exports = {
    AuthType,
    WorkoutType,
    UserType,
    MealType,
    NutritionType
}

I suspect the error I am getting is due to mergeSchema object from graphql-tools, maybe it cannot merge the GraphQLSchema types properly? I am not sure. Any help is appreciated!

Answer 1

mergeSchemas is intended to be used with schema stitching . It should not be used just to modularize your single schema, which is what you're trying to do here.

You should only create a single GraphQLSchema object, a single GraphQLObjectType for your query root type and a single GraphQLObjectType for your mutation root type. If you want the fields for a specific type, like your Mutation type, to be spread across multiple modules, then you should export just those fields , not an entire type or schema.

module.exports = {
  queries: {
    workout: { ... },
    workouts: { ... },
  },
  mutations: {
    addWorkout: { ... },
  },
}

Whatever file you create your schema in can then import these fields from multiple modules and combine them into an individual schema.

const query = new GraphQLObjectType({
  name: 'Query',
  fields: () => ({
    ...require('moduleA').queries,
    ...require('moduleB').queries,
    ...require('moduleC').queries,
  }),
})
const mutation = new GraphQLObjectType({ ... })
const schema = new GraphQLSchema({ query, mutation })