graphql-non-null-directive

Makes your GraphQL input optional, but not null!

The problem

GraphQL Thread from 2018

It's common for Update mutations to accept a partial input, in order to do a partial update.

The simplest version of this is to simply omit the non-nullish (!) operator in the input declaration, and not update anything that's nullish:

``graphql
input UpdateUserInput {
firstName: String
lastName: String
country: String
# ...
}
`

The issue with this is that you lose the ability to say "if provided, this field cannot be null"

With a @nonNull directive, you get this ability back:

`graphql
input UpdateUserInput {
firstName: String @nonNull
lastName: String @nonNull
country: String
# ...
}
`

$3

The @nonNull directive cannot be used on Argument Definitions.
That is because, unlike in Object Inputs, GraphQL.js will always default optional arguments to null.

Instead of:

`graphql


this does not work!


type Mutation {
updateUser(firstName: String @nonNull): User
}
`

Do:

`graphql


this works!

type Mutation {
updateUser(input: UpdateUserInput!): User
}

input UpdateUserInput {
firstName: String @nonNull
# ...
}
`

Usage

*NB: This library is built using graphql-tools and should be compatible with apollo

- Install from npm: npm i @ephys/graphql-non-null-directive
- Declare the directive in your schema:
`graphql
directive @nonNull on INPUT_FIELD_DEFINITION
`
- Declare the directive in your Apollo Server:
`typescript
import { createNonNullDirective } from '@ephys/graphql-non-null-directive';

const server = new ApolloServer({
// ...
schemaDirectives: {
nonNull: createNonNullDirective({
// (optional) use this property to change the ID of the directive
directiveName: 'nonNull',
// (optional) use this property to configure how Input Errors are built
// Input Errors are thrown when a @nonNull input received null..
buildInputError: (message: string) => {
return new Error(message);
},
}),
},
});
``