Overview

This upgrade guide describes how to migrate a Node.js project that's based on Prisma 1 and uses prisma-binding to implement a GraphQL server.

The code will be migrated to @nexus/schema and the nexus-plugin-prisma. As opposed to the SDL-first approach that's used with prisma-binding, Nexus follows a code-first approach to construct GraphQL schemas. You can learn about the main differences of these two approaches in this article. If you want to continue using the SDL-first approach, you can follow the guide to upgrade from prisma-binding to an SDL-first setup.

This guide also explains how to migrate from JavaScript to TypeScript, it therefore basically assumes a full rewrite of your existing app. If you want to keep running your application in JavaScript, you can ignore the instructions that relate to the TypeScript setup keep using JavaScript as before.

The guide assumes that you already went through the guide for upgrading the Prisma layer. This means you already:

  • installed the Prisma 2.0 CLI
  • created your Prisma 2.0 schema
  • introspected your database and resolved potential schema incompatibilities
  • installed and generated Prisma Client

The guide further assumes that you have a file setup that looks similar to this:

.
├── README.md
├── package.json
├── prisma
│ └── schema.prisma
├── prisma1
│ ├── datamodel.prisma
│ └── prisma.yml
└── src
├── generated
│ └── prisma.graphql
├── index.js
└── schema.graphql

The important parts are:

  • A folder called with prisma with your Prisma 2.0 schema
  • A folder called src with your application code and a schema called schema.graphql

If this is not what your project structure looks like, you'll need to adjust the instructions in the guide to match your own setup.

1. Installing and configuring Nexus

1.1. Install Nexus dependencies

The first step is to install the Nexus dependency in your project:

$npm install @nexus/schema

Next, install the the Prisma plugin for Nexus which will allow you to expose Prisma models in your GraphQL API:

$npm install nexus-plugin-prisma

The nexus-plugin-prisma dependency bundles all required Prisma dependencies. You should therefore remove the dependencies that you installed when you upgraded the Prisma layer of your app:

$npm uninstall @prisma/cli @prisma/client

Note however that you can still invoke the Prisma 2.0 CLI with the familiar command:

$npx prisma

1.2. Configure TypeScript

Since you'll be using TypeScript in this guide, you need to add the required dependencies:

$npm install typescript ts-node-dev --save-dev

Create a new file called tsconfig.json in the root directory of your project:

$touch tsconfig.json

Now add the following contents to the new file:

tsconfig.json
1{
2 "compilerOptions": {
3 "skipLibCheck": true,
4 "strict": true,
5 "rootDir": "src",
6 "noEmit": true
7 },
8 "include": ["src/**/*"]
9}

1.3. Create your basic Nexus setup

Create the root source file of your API called index.ts inside the src directory:

$touch src/index.ts

Note that for this guide, you'll write the entire application inside of index.ts. In practice, you probably want to split your GraphQL types across different files as shown in this example.

For some basic setup, add this code to index.ts:

index.ts
1import { queryType, makeSchema } from "@nexus/schema"
2import { nexusSchemaPrisma } from "nexus-plugin-prisma/schema"
3import { GraphQLServer } from "graphql-yoga"
4import { createContext } from "./context"
5
6const Query = queryType({
7 definition(t) {
8 t.string("hello", () => {
9 return "Hello Nexus!"
10 })
11 },
12})
13
14export const schema = makeSchema({
15 types: [Query],
16 plugins: [nexusSchemaPrisma({ experimentalCRUD: true })],
17 outputs: {
18 schema: __dirname + '/../schema.graphql',
19 typegen: __dirname + '/generated/nexus.ts',
20 },
21 typegenAutoConfig: {
22 contextType: "Context.Context",
23 sources: [
24 {
25 source: "@prisma/client",
26 alias: "prisma",
27 },
28 {
29 source: require.resolve("./context"),
30 alias: "Context",
31 },
32 ],
33 },
34})
35
36new GraphQLServer({ schema, context: createContext() }).start(() =>
37 console.log(
38 `Server ready at: http://localhost:4000`,
39 ),
40)

Note that this setup already contains the configuration of the Prisma plugin for Nexus. This will enable the t.model and t.crud functionality that you'll get to know later in this guide.

In the typegenAutoConfig setting, you're providing additional types that help your editor to provide your autocompletion as you develop your app. Right now it references a file called types.ts that you don't have in your project yet. This file will contain the type of your context object that's passed through your GraphQL resolver chain.

Create the new types.ts file inside the src directory:

$touch src/types.ts

Now add the following code to it:

import { PrismaClient } from '@prisma/client'
const prisma = new PrismaClient()
export interface Context {
prisma: PrismaClient
}
export function createContext(): Context {
return { prisma }
}

Next, adjust the scripts section inside your package.json to include the following commands:

{
"scripts": {
"start": "node dist/server",
"clean": "rm -rf dist",
"build": "npm -s run clean && npm -s run generate && tsc",
"generate": "npm -s run generate:prisma && npm -s run generate:nexus",
"generate:prisma": "prisma generate",
"generate:nexus": "ts-node --transpile-only src/schema",
"dev": "ts-node-dev --no-notify --respawn --transpile-only src"
}
}

The dev script starts a development server that you always should have running in the background when developing your app. This is important because of the code generation Nexus performs in the background.

You can start the development server using the following command:

npm run dev

You should see the following CLI output:

$Server ready at: http://localhost:4000

Your GraphQL server is now running at http://localhost:4000. So far it implements a single GraphQL query that you can send as follows:

{
hello
}

In the following steps, we'll explain how you can migrate your existing SDL-first GraphQL schema that's implemented with prisma-binding to an equivalent setup using Nexus.

2. Create your GraphQL types

The next step of the upgrade process is to create your GraphQL types. In this case, your GraphQL types will mirror the Prisma models (as it likely was the case in your prisma-binding setup as well). If a GraphQL type deviates from a Prisma model, you'll be able to easily adjust the exposed GraphQL type accordingly using the Nexus API.

For the purpose of this guide, you'll keep all the code in a single file. However, you can structure the files to your personal preference and import accordingly.

In Nexus, GraphQL types are defined via the objectType function. Import objectType and then start with the skeleton for your first GraphQL type. In this case, we're starting by mapping Prisma's User model to GraphQL:

import { objectType } from 'nexus'
const User = objectType({
name: 'User',
definition(t) {
// the fields of the type will be defined here
},
})

With this code in place, you can start exposing the fields of the User model one by one. You can use your editor's autocompletion to save some typing. Inside the body of the definition function, type t.model. and then hit CTRL+SPACE. This will bring up the autocompletion and suggest all fields that are defined on the User model:

Note that the model property on t is provided by the nexus-plugin-prisma. It leverages the type information from your Prisma schema and lets you expose your Prisma models via GraphQL.

In that manner, you can start completing your object type definition until you exposed all the fields of the model:

const User = objectType({
name: 'User',
definition(t) {
t.model.id()
t.model.email()
t.model.name()
t.model.jsonData()
t.model.role()
t.model.profile()
t.model.posts()
},
})

At this point, any relation fields might give you TypeScript errors (in this case, that would be profile and posts which both point to other object types). That's expected, these errors will resolve automatically after you've added the remaining types.

Note: Be sure to have your Nexus development server that you started with npm run dev running all the time. It constantly updates the generated Nexus types that enable the autocompletion in the background as you save a file.

Note that the t.model.posts relation exposes a list of Post objects. By default, Nexus exposes only pagination properties for that list – if you want to add ordering and filtering for that relation as well, you'll need to explicitly enable those:

const User = objectType({
name: 'User',
definition(t) {
t.model.id()
t.model.email()
t.model.name()
t.model.jsonData()
t.model.role()
t.model.profile()
t.model.posts({
filtering: true,
ordering: true,
})
},
})

After defining a type using the objectType function, you also need to manually add it to your GraphQL schema that you're building with Nexus. You can do it by adding it to the types which are provided as an option to the makeSchema function:

export const schema = makeSchema({
types: [Query, User],
plugins: [nexusSchemaPrisma()],
outputs: {
schema: __dirname + '/../schema.graphql',
typegen: __dirname + '/generated/nexus.ts',
},
typegenAutoConfig: {
sources: [
{
source: '@prisma/client',
alias: 'prisma',
},
],
},
})

Once you're done with the first type, you can start defining the remaining ones.

To expose all sample Prisma models with Nexus, the following code is needed:

const User = objectType({
name: 'User',
definition(t) {
t.model.id()
t.model.email()
t.model.name()
t.model.jsonData()
t.model.role()
t.model.profile()
t.model.posts({
filtering: true,
ordering: true,
})
},
})
const Post = objectType({
name: 'Post',
definition(t) {
t.model.id()
t.model.createdAt()
t.model.updatedAt()
t.model.title()
t.model.content()
t.model.published()
t.model.author()
t.model.authorId()
t.model.categories({
filtering: true,
ordering: true,
})
},
})
const Profile = objectType({
name: 'Profile',
definition(t) {
t.model.id()
t.model.bio()
t.model.userId()
t.model.user()
},
})
const Category = objectType({
name: 'Category',
definition(t) {
t.model.id()
t.model.name()
t.model.posts({
filtering: true,
ordering: true,
})
},
})

Be sure to include all newly defined types in the types option that's provided to makeSchema:

export const schema = makeSchema({
types: [Query, User, Post, Profile, Category],
plugins: [nexusSchemaPrisma()],
outputs: {
schema: __dirname + '/../schema.graphql',
typegen: __dirname + '/generated/nexus.ts',
},
typegenAutoConfig: {
sources: [
{
source: '@prisma/client',
alias: 'prisma',
},
],
},
})

You can view the current version of your GraphQL schema in SDL in the generated GraphQL schema file in ./schema.graphql.

3. Migrate GraphQL operations

As a next step, you can start migrating all the GraphQL queries and mutations from the "previous" GraphQL API to the new one that's built with Nexus.

For this guide, the following sample GraphQL schema will be used:

# import Post from './generated/prisma.graphql'
# import User from './generated/prisma.graphql'
# import Category from './generated/prisma.graphql'
input UserUniqueInput {
id: String
email: String
}
type Query {
posts(searchString: String): [Post!]!
user(userUniqueInput: UserUniqueInput!): User
users(where: UserWhereInput, orderBy: Enumerable<UserOrderByInput>, skip: Int, after: String, before: String, first: Int, last: Int): [User]!
}
type Mutation {
createUser(data: UserCreateInput!): User!
createDraft(title: String!, content: String, authorId: ID!): Post
updateBio(userUniqueInput: UserUniqueInput!, bio: String!): User
addPostToCategories(postId: String!, categoryIds: [String!]!): Post
}

3.1. Migrate GraphQL queries

In this section, you'll migrate all GraphQL queries from prisma-binding to Nexus.

3.1.1. Migrate the users query (which uses forwardTo)

In our sample API, the users query from the sample GraphQL schema is defined and implemented as follows.

SDL schema definition with prisma-binding
type Query {
users(where: UserWhereInput, orderBy: Enumerable<UserOrderByInput>, skip: Int, after: String, before: String, first: Int, last: Int): [User]!
# ... other queries
}
Resolver implementation with prisma-binding
const resolvers = {
Query: {
users: forwardTo('prisma'),
// ... other resolvers
}
}

To mirror the same behaviour with Nexus, you can use the crud property on the t variable inside the definition function.

Similar to model, this property is available because you're using the nexus-prisma-plugin which leverages type information from your Prisma models and auto-generates resolvers under the hood. The crud property also supports autocompletion, so you can explore all available queries in your editor again:

Forwarding the query with the nexus-prisma-plugin

To add the users query to your GraphQL API, add the following lines to the query type definition:

const Query = queryType({
definition(t) {
t.crud.users({
filtering: true,
ordering: true,
})
}
})

If you have the Nexus development server running, you can save the file and your GraphQL API will be updated to expose the new users query. You can also observe this by looking at the Query type inside the generated schema.graphql file:

type Query {
users(after: UserWhereUniqueInput, before: UserWhereUniqueInput, first: Int, last: Int, orderBy: Enumerable<UserOrderByInput>, skip: Int, where: UserWhereInput): [User!]!
}

You can now write your first query against the new API, e.g.:

{
users {
id
name
profile {
id
bio
}
posts {
id
title
categories {
id
name
}
}
}
}

If your application exposes all CRUD operations from Prisma using forwardTo, you can now continue adding all remaining ones using the same approach via t.crud. To learn how "custom" queries can be defined and resolved using Nexus, move on to the next sections.

3.1.2. Migrate the posts(searchString: String): [Post!]! query

The posts query is defined and implemented as follows.

SDL schema definition with prisma-binding
type Query {
posts(searchString: String): [Post!]!
# ... other queries
}
Resolver implementation with prisma-binding
const resolvers = {
Query: {
posts: (_, args, context, info) => {
return context.prisma.query.posts(
{
where: {
OR: [
{ title_contains: args.searchString },
{ content_contains: args.searchString },
],
},
},
info,
)
},
// ... other resolvers
}
}
Code-first schema definition with nexus

To get the same behaviour with Nexus, you'll need to add a t.field definition to the queryType:

const Query = queryType({
definition(t) {
// ... previous queries
t.list.field('posts', {
type: 'Post',
nullable: false,
args: { searchString: stringArg() }
})
}
})

Although this code gives probably gives you a type error in your editor, you can already look at the generated SDL version of your GraphQL schema inside schema.graphql. You'll notice that this has added the correct definition to your GraphQL schema already:

type Query {
posts(searchString: String): [Post!]!
users(after: UserWhereUniqueInput, before: UserWhereUniqueInput, first: Int, last: Int, orderBy: Enumerable<UserOrderByInput>, skip: Int, where: UserWhereInput): [User!]!
}

However, the code is missing the actual resolver logic. This is what you're going to add next.

Resolver implementation with nexus

You can add the resolver with Nexus as follows:

const Query = queryType({
definition(t) {
// ... previous queries
t.list.field('posts', {
type: 'Post',
nullable: false,
args: { searchString: stringArg() },
resolve: (_, args, context) => {
return context.prisma.post.findMany({
where: {
OR: [{
title: { contains: args.searchString }
}, {
content: { contains: args.searchString }
}]
}
})
}
})
}
})

To validate the implementation, you can now e.g. send the following example query to your GraphQL server:

{
posts {
id
title
author {
id
name
}
}
}

3.1.2. Migrate the user(uniqueInput: UserUniqueInput): User query

In our sample app, the user query is defined and implemented as follows.

SDL schema definition with prisma-binding
type Query {
user(userUniqueInput: UserUniqueInput): User
# ... other queries
}
input UserUniqueInput {
id: String
email: String
}

Note that this is a bit of a contrived example to demonstrate the usage of input types with Nexus.

Resolver implementation with prisma-binding
const resolvers = {
Query: {
user: (_, args, context, info) => {
return context.prisma.query.user(
{
where: args.userUniqueInput,
},
info,
)
},
// ... other resolvers
}
}
Code-first schema definition with nexus

To get the same behaviour with Nexus, you'll need to add a t.field definition to the queryType and define an inputObjectType that includes the two @unique fields of your User model:

import { inputObjectType, arg } from "@nexus/schema"
const UserUniqueInput = inputObjectType({
name: 'UserUniqueInput',
definition(t) {
t.string('id')
t.string('email')
},
})
const Query = queryType({
definition(t) {
// ... previous queries
t.field('user', {
type: 'User',
args: {
userUniqueInput: arg({
type: 'UserUniqueInput',
nullable: false,
})
}
})
}
})

Since UserUniqueInput is a new type in your GraphQL schema, you again need to add it to the types option that's passed to makeSchema:

export const schema = makeSchema({
types: [Query, User, Post, Profile, Category, UserUniqueInput],
plugins: [nexusSchemaPrisma()],
outputs: {
schema: __dirname + '/../schema.graphql',
typegen: __dirname + '/generated/nexus.ts',
},
typegenAutoConfig: {
sources: [
{
source: '@prisma/client',
alias: 'prisma',
},
],
},
})

If you look at the generated SDL version of your GraphQL schema inside schema.graphql, you'll notice that this change already added the correct definition to your GraphQL schema:

type Query {
posts(searchString: String): [Post!]
user(userUniqueInput: UserUniqueInput!): User
users(after: UserWhereUniqueInput, before: UserWhereUniqueInput, first: Int, last: Int, orderBy: Enumerable<UserOrderByInput>, skip: Int, where: UserWhereInput): [User!]!
}
input UserUniqueInput {
email: String
id: String
}

You can even send the respective query via the GraphQL Playground already:

{
user(userUniqueInput: { email: "alice@prisma.io" }) {
id
name
}
}

However, because the resolver is not yet implemented you will not get any data back yet.

Code-first resolver implementation with nexus

That's because you're still missing the resolver implementation for that query. You can add the resolver with Nexus as follows:

const UserUniqueInput = inputObjectType({
name: 'UserUniqueInput',
definition(t) {
t.string('id')
t.string('email')
},
})
const Query = queryType({
definition(t) {
// ... previous queries
t.field('user', {
type: 'User',
nullable: true,
args: {
userUniqueInput: arg({
type: 'UserUniqueInput',
nullable: false,
})
},
resolve: (_, args, context) => {
return context.prisma.user.findOne({
where: {
id: args.userUniqueInput?.id,
email: args.userUniqueInput?.email
}
})
}
})
},
}
})

If you're re-sending the same query from before, you'll find that it now returns actual data.

3.2. Migrate GraphQL mutations

In this section, you'll migrate the GraphQL mutations from the sample schema to the Nexus.

3.2.1. Define the Mutation type

The first step to migrate any mutations is to define the Mutation type of your GraphQL API. Once that's done, you can gradually add operations to it. Add the following definition to index.ts:

import { mutationType } from "@nexus/schema"
const Mutation = mutationType({
definition(t) {
// your GraphQL mutations + resolvers will be defined here
}
})

In order to make sure that the new Mutation type is picked by up Nexus, you need to add it to the types that are provided to makeSchema:

export const schema = makeSchema({
types: [Query, User, Post, Profile, Category, UserUniqueInput, Mutation],
plugins: [nexusSchemaPrisma()],
outputs: {
schema: __dirname + '/../schema.graphql',
typegen: __dirname + '/generated/nexus.ts',
},
typegenAutoConfig: {
sources: [
{
source: '@prisma/client',
alias: 'prisma',
},
],
},
})

3.2.2. Migrate the createUser mutation (which uses forwardTo)

In the sample app, the createUser mutation from the sample GraphQL schema is defined and implemented as follows.

SDL schema definition with prisma-binding
type Mutation {
createUser(data: UserCreateInput!): User!
# ... other mutations
}
Resolver implementation with prisma-binding
const resolvers = {
Mutation: {
createUser: forwardTo('prisma'),
// ... other resolvers
}
}

Similar to forwarding GraphQL queries, you can use the crud property on the t variable inside the definition function in order to expose full CRUD capabilities for Prisma models.

Similar to model, this property is available because you're using the nexus-prisma-plugin which leverages type information from your Prisma models and auto-generates resolvers under the hood. The crud property supports autocompletion when defining mutations as well, so you can explore all available operations in your editor again:

Forwarding the mutation with the nexus-prisma-plugin

To add the createUser mutation to your GraphQL API, add the following lines to the query type definition:

const Mutation = mutationType({
definition(t) {
t.crud.createOneUser({
alias: 'createUser',
})
}
})

Note that the default name for the mutation in your GraphQL schema is createOneUser (named after the function which is exposed by t.crud). In order to rename it to createUser, you need to provide the alias property.

If you have the Nexus development server running, you can save the file and your GraphQL API will be updated to expose the new createUser mutation. You can also observe this by looking at the Mutation type inside the generated schema.graphql file:

type Mutation {
createUser(data: UserCreateInput!): User!
}

You can now write your first mutation against the new API, e.g.:

mutation {
createUser(data: {
name: "Alice",
email: "alice@prisma.io"
}) {
id
}
}

If your application exposes all CRUD operations from Prisma using forwardTo, you can now continue adding all remaining ones using the same approach via t.crud. To learn how "custom" mutations can be defined and resolved using Nexus, move on to the next sections.

3.2.3. Migrate the createDraft(title: String!, content: String, authorId: String!): Post! query

In the sample app, the createDraft mutation is defined and implemented as follows.

SDL schema definition with prisma-binding
type Mutation {
createDraft(title: String!, content: String, authorId: String!): Post!
# ... other mutations
}
Resolver implementation with prisma-binding
const resolvers = {
Mutation: {
createDraft: (_, args, context, info) => {
return context.prisma.mutation.createPost(
{
data: {
title: args.title,
content: args.content,
author: {
connect: {
id: args.authorId,
},
},
},
},
info,
)
},
// ... other resolvers
}
}
Code-first schema definition with nexus

To get the same behaviour with Nexus, you'll need to add a t.field definition to the mutationType:

const Mutation = mutationType({
definition(t) {
// ... previous mutations
t.field('createDraft', {
type: 'Post',
args: {
title: stringArg({ nullable: false }),
content: stringArg(),
authorId: stringArg({ nullable: false }),
}
})
}
})

If you look at the generated SDL version of your GraphQL schema inside schema.graphql, you'll notice that this has added the correct definition to your GraphQL schema already:

type Mutation {
createUser(data: UserCreateInput!): User!
createDraft(title: String!, content: String, authorId: String!): Post!
}

You can even send the respective mutation via the GraphQL Playground already:

mutation {
createDraft(
title: "Hello World",
authorId: "__AUTHOR_ID__"
) {
id
published
author {
id
name
}
}
}

However, because the resolver is not yet implemented, no new Post record will be created and you will not get any data back in the response.

Resolver implementation with nexus

That's because you're still missing the resolver implementation for that mutation. You can add the resolver with Nexus as follows:

const Mutation = mutationType({
definition(t) {
// ... previous mutations
t.field('createDraft', {
type: 'Post',
args: {
title: stringArg({ nullable: false }),
content: stringArg(),
authorId: stringArg({ nullable: false }),
},
resolve: (_, args, context) => {
return context.prisma.post.create({
data: {
title: args.title,
content: args.content,
author: {
connect: { id: args.authorId }
}
}
})
}
})
}
})

If you're re-sending the same query from before, you'll find that it now create a new Post record and return valid data.

3.2.4. Migrate the updateBio(bio: String, userUniqueInput: UserUniqueInput!): User mutation

In the sample app, the updateBio mutation is defined and implemented as follows.

SDL schema definition with prisma-binding
type Mutation {
updateBio(bio: String!, userUniqueInput: UserUniqueInput!): User
# ... other mutations
}
Resolver implementation with prisma-binding
const resolvers = {
Mutation: {
updateBio: (_, args, context, info) => {
return context.prisma.mutation.updateUser(
{
data: {
profile: {
update: { bio: args.bio }
}
},
where: { id: args.userId }
},
info,
)
},
// ... other resolvers
}
}
Code-first schema definition with nexus

To get the same behaviour with Nexus, you'll need to add a t.field definition to the mutationType:

const Mutation = mutationType({
definition(t) {
// ... previous mutations
t.field('updateBio', {
type: 'User',
args: {
userUniqueInput: arg({
type: 'UserUniqueInput',
nullable: false
}),
bio: stringArg({ nullable: false })
},
})
}
})

If you look at the generated SDL version of your GraphQL schema inside schema.graphql, you'll notice that this has added the correct definition to your GraphQL schema already:

type Mutation {
createUser(data: UserCreateInput!): User!
createDraft(title: String!, content: String, authorId: String!): Post!
updateBio(bio: String!, userUniqueInput: UserUniqueInput!): User
}

You can even send the respective mutation via the GraphQL Playground already:

mutation {
updateBio(
userUniqueInput: {
email: "alice@prisma.io"
}
bio: "I like turtles"
){
id
name
profile {
id
bio
}
}
}

However, because the resolver is not yet implemented, nothing will be updated in the database and you will not get any data back in the response.

Resolver implementation with nexus

That's because you're still missing the resolver implementation for that query. You can add the resolver with Nexus as follows:

const Mutation = mutationType({
definition(t) {
// ... previous mutations
t.field('updateBio', {
type: 'User',
args: {
userUniqueInput: arg({
type: 'UserUniqueInput',
nullable: false
}),
bio: stringArg()
},
resolve: (_, args, context) => {
return context.prisma.user.update({
where: {
id: args.userUniqueInput?.id,
email: args.userUniqueInput?.email
},
data: {
profile: {
create: { bio: args.bio }
}
}
})
}
}
})

If you're re-sending the same query from before, you'll find that it now returns actual data instead of null.

3.2.5. Migrate the addPostToCategories(postId: String!, categoryIds: [String!]!): Post mutation

In our sample app, the addPostToCategories mutation is defined and implemented as follows.

SDL schema definition with prisma-binding
type Mutation {
addPostToCategories(postId: String!, categoryIds: [String!]!): Post
# ... other mutations
}
Resolver implementation with prisma-binding
const resolvers = {
Mutation: {
addPostToCategories: (_, args, context, info) => {
const ids = args.categoryIds.map(id => ({ id }))
return context.prisma.mutation.updatePost(
{
data: {
categories: {
connect: ids
}
},
where: {
id: args.postId
}
},
info,
)
},
// ... other resolvers
}
}
Code-first schema definition with nexus

To get the same behaviour with Nexus, you'll need to add a t.field definition to the mutationType:

const Mutation = mutationType({
definition(t) {
// ... mutations from before
t.field('addPostToCategories', {
type: 'Post',
args: {
postId: stringArg({ nullable: false }),
categoryIds: stringArg({
list: true,
nullable: false
}),
},
})
}
})

If you look at the generated SDL version of your GraphQL schema inside schema.graphql, you'll notice that this has added the correct definition to your GraphQL schema already:

type Mutation {
createUser(data: UserCreateInput!): User!
createDraft(title: String!, content: String, authorId: String!): Post!
updateBio(bio: String, userUniqueInput: UserUniqueInput!): User
addPostToCategories(postId: String!, categoryIds: [String!]!): Post
}

You can even send the respective query via the GraphQL Playground already:

mutation {
addPostToCategories(
postId: "__AUTHOR_ID__"
categoryIds: [
"__CATEGORY_ID_1__",
"__CATEGORY_ID_2__",
]
) {
id
title
categories {
id
name
}
}
}

However, because the resolver is not yet implemented, nothing will be updated in the database and you will not get any data back in the response.

Resolver implementation with nexus

That's because you're still missing the resolver implementation for that query. You can add the resolver with Nexus as follows:

const Mutation = mutationType({
definition(t) {
// ... mutations from before
t.field('addPostToCategories', {
type: 'Post',
args: {
postId: stringArg({ nullable: false }),
categoryIds: stringArg({
list: true,
nullable: false
}),
},
resolve: (_, args, context) => {
const ids = args.categoryIds.map(id => ({ id }))
return context.prisma.post.update({
where: {
id: args.postId
},
data: {
categories: { connect: ids }
}
})
}
})
}
})

If you're re-sending the same query from before, you'll find that it now returns actual data instead of null.

4. Cleaning up

Since the entire app has now been upgrade to Prisma 2.0 and Nexus, you can delete all unnecessary files and remove the no longer needed dependencies.

4.1. Clean up npm dependencies

You can start by removing npm dependencies that were related to the Prisma 1 setup:

npm uninstall graphql-cli prisma-binding prisma1

4.2. Delete unused files

Next, delete the files of your Prisma 1 setup:

rm prisma1/datamodel.prisma prisma1/prisma.yml

You can also delete any remaining .js files, the old schema.graphql and prisma.graphql files.

4.3. Stop the Prisma server

Finally, you can stop running your Prisma server.

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