How to execute a mutation in GraphQL? - node.js

Question

In GraphQL we have basically two types of operations: queries and mutations. While queries are well described in the documentation and there are many examples of them, I'm having a hard time to understand how to execute a mutation. Mutations obviously are update methods.
I've created very simple Node.js server:
var express = require("express");
var graphqlHTTP = require("express-graphql");
var graphql = require("graphql");
var inMemoryDatabase = require("./inMemoryDatabase").inMemoryDatabase;
var _ = require("lodash-node");
var userType = new graphql.GraphQLObjectType({
name: "User",
fields: {
id: { type: graphql.GraphQLString },
name: { type: graphql.GraphQLString }
}
});
var queryType = new graphql.GraphQLObjectType({
name: "Query",
fields: {
user: {
type: userType,
args: {
id: { type: graphql.GraphQLString }
},
resolve: function(parent, { id }) {
return _.find(inMemoryDatabase, { id: id });
}
}
}
});
var mutationType = new graphql.GraphQLObjectType({
name: "Mutation",
fields: {
user: {
type: userType,
args: {
id: { type: graphql.GraphQLString },
name: { type: graphql.GraphQLString }
},
resolve: function(parent, { id, name }) {
var index = _.findIndex(inMemoryDatabase, { id: id });
inMemoryDatabase.splice(index, 1, { id: id, name: name });
return _.find(inMemoryDatabase, { id: id });
}
}
}
});
var schema = new graphql.GraphQLSchema({
query: queryType,
mutation: mutationType
});
var app = express();
app.use(
"/graphql",
graphqlHTTP({
schema: schema,
graphiql: true
})
);
var port = 9000;
if (process.env.PORT) {
port = process.env.PORT;
}
app.listen(port);
console.log("Running a GraphQL API server at localhost:" + port + "/graphql");
In memory database is just in an array of User objects {id, name}:
var inMemoryDatabase = [
{
id: "31ce0260-2c23-4be5-ab78-4a5d1603cbc8",
name: "Mark"
},
{
id: "2fb6fd09-2697-43e2-9404-68c2f1ffbf1b",
name: "Bill"
}
];
module.exports = {
inMemoryDatabase
};
Executing query to get user by id looks as follows:
{
user(id: "31ce0260-2c23-4be5-ab78-4a5d1603cbc8"){
name
}
}
How would the mutation changing user name look like?

Answer 1

Hey may completely be missing what you are saying, but the way that I look at a mutation is like this
I get some arguments and a field, that is the same thing as params and a path in rest, with those i do something (in your case lookup the user and update the attribute based on the arguments passed in
After That, i return something from the resolve function that will fulfill the type you specify in the type of the mutation
var mutationType = new graphql.GraphQLObjectType({
name: "Mutation",
fields: {
user: {
// You must return something from your resolve function
// that will fulfill userType requirements
type: userType,
// with these arguments, find the user and update them
args: {
id: { type: graphql.GraphQLString },
name: { type: graphql.GraphQLString }
},
// this does the lookup and change of the data
// the last step of your result is to return something
// that will fulfill the userType interface
resolve: function(parent, { id, name }) {
// Find the user, Update it
// return something that will respond to id and name, probably a user object
}
}
}
});
Then with that as a context, you pass some arguments and request back a user
mutation updateUser {
user(id: "1", name: "NewName") {
id
name
}
}
In a normal production schema you would also normally have something like errors that could be returned to convey the different states of the update for failed/not found

Answer 2

#Austio's answer was pretty close, but the proper way is:
mutation updateUser {
user(id: "31ce0260-2c23-4be5-ab78-4a5d1603cbc8", name: "Markus") {
id
name
}
}

Answer 3

if we connect directly with MongoDB below will help you.
mutation {
taskTrackerCreateOne
(
record:
{
id:"63980ae0f019789eeea0cd33",
name:"63980c86f019789eeea0cda0"
}
)
{
recordId
}
}