graphql-prisma-select

A lightweight utility to convert GraphQL ResolveInfo into a Prisma select object. This allows you to automatically fetch only the fields requested by the GraphQL client, resolving the "over-fetching" problem and optimizing database performance.

Features

• Zero Dependencies: Only requires graphql as a peer dependency.
• Support for Fragments: Handles both inline and named fragments.
• Nested Relations: Recursively builds selection sets for related models.
• Field Exclusion: Easily exclude specific fields (like sensitive data or virtual fields) from the database query.
• JSON Fields Handling: Specifically resolve fields to true to avoid Prisma unsupported nested JSON selections errors.

Installation

npm install graphql-prisma-select

yarn add graphql-prisma-select

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Usage

Basic Usage with Prisma

In your resolver, pass the info object to prismaSelect and spread the result into your Prisma query.

import { prismaSelect } from 'graphql-prisma-select'
const resolvers = {
  Query: {
    users: async (parent, args, context, info) => {
      const select = prismaSelect(info)
      // Equivalent to: prisma.user.findMany({ select: { id: true, email: true, ... } })
      return context.prisma.user.findMany({
        ...args, // pagination, filtering, etc.
        select,
      })
    },
    user: async (parent, { id }, context, info) => {
      const select = prismaSelect(info)
      return context.prisma.user.findUnique({
        where: { id },
        select,
      })
    },
  },
}

Global Configuration

You can set default options globally, which will be used if not provided in the prismaSelect function call.

import { setGlobalPrismaSelectOptions } from 'graphql-prisma-select'
setGlobalPrismaSelectOptions({
  excludeFields: ['password'],
  jsonFields: ['metadata'],
})

Excluding Fields

You can exclude specific fields from being selected in the database, for example, if they are computed fields or sensitive data that you want to handle manually or via a different mechanism.

const select = prismaSelect(info, {
  excludeFields: ['password', 'virtualField'],
})

Handling Prisma JSON Fields

Prisma does not support sub-field selections on Json columns. If your GraphQL schema defines a structured type for a JSON column, prismaSelect will attempt to create a nested select object, which causes Prisma to throw an error (not implemented: SelectionSetOnScalar). To fix this, pass the names of your JSON fields into the jsonFields array option. This forces the utility to select the entire JSON object (true) instead of building a sub-selection.

const select = prismaSelect(info, {
  jsonFields: ['attachments', 'metadata', 'config'],
})

Compatibility

Works with:

• Apollo Server
• Mercurius (Fastify)
• GraphQL Yoga
• Any standard GraphQL server that provides GraphQLResolveInfo.

License

MIT