Does Fauna support input variable injection in GraphQL mutations? All of the examples I see in the docs use inline data for mutations, like this:
(from: GraphQL relationships | Fauna Documentation)
mutation {
createUser(data: {
name: "Jane"
cars: {
create: [
{ plate: "AAA-1234" }
{ plate: "BBB-123" }
]
}
}) {
_id
name
cars {
data {
plate
}
}
}
}
However, I’d like to set up the mutation like this, with the data set to a variable that will be injected later by the query library:
mutation CreateUser($data: CreateUserInput!) {
createUser(data: $data) {
_id
name
cars {
data {
plate
}
}
}
}
The difference being that the data variable can be passed in after the mutation is declared. This is common practice when using Apollo Client’s useMutation hook. Typically, you would declare a mutation outside of a React component, like this:
import React from 'react';
import { gql, useMutation } from '@apollo/client';
const CREATE_USER = gql`
mutation CreateUser($data: CreateUserInput!) {
createUser(data: $data) {
_id
name
cars {
data {
plate
}
}
}
}
`;
const UserProfile = () => {
const [createUser, { data, loading, error }] = useMutation(CREATE_USER);
// After a form submission, you would do this:
createUser({
variables: {
data: { // this data would come from user input, so it can't be added to the
// CREATE_USER mutation ahead of time
name: "Jane"
cars: {
create: [
{ plate: "AAA-1234" }
{ plate: "BBB-123" }
]
}
}
}
})
// Rest of component code goes here ...
}
I tested this within the Fauna GraphQL playground by setting up a new database and populating it with the default test data. I can see that two equivalent mutations with an inline variable vs. an injected variable will work differently. The mutation using an inline variable succeeds; the one with an injected variable fails.
Is this expected? Am I doing something wrong?
