graphql-transform-schema

Transform, filter & alias resolvers of a GraphQL schema

Install

yarn add graphql-transform-schema

Usage

By default transformSchema passes through all queries/mutations. (Open Demo)

import { transformSchema } from 'graphql-transform-schema'

// needed for remote schemas
import { createApolloFetch } from 'apollo-fetch'
import { makeRemoteExecutableSchema } from 'graphql-tools'

const schema = await makeRemoteExecutableSchema(createApolloFetch({
  uri: 'https://api.graph.cool/simple/v1/swapi',
}))

// hide every query/mutation except the `Starship` and `allStarships` query
const transformedSchema = transformSchema(schema, {
  '*': false,
  Starship: true,
  allStarships: true,
})

const transformedSchema = transformSchema(schema, {
  Query: {
    '*': false,
    Starship: true,
    allStarships: true,
  },
  Mutation: {
  
  },
  Starship: {
    '*': false,
    id: true,
  },
})

API

interface Rules {
  [fieldName: string]: boolean | Function
}

function transformSchema(schema: GraphQLSchema, rules: Rules): GraphQLSchema

Examples

Remove all createX and deleteX mutations

const transformedSchema = transformSchema(schema, {
  'create*': false,
  'delete*': false,
})

Overwrite resolved data

const typeDefs = `
  type Query {
    hello: String!
  }

  type Mutation {
    alexaHello(name: String!): String!
  }
`
const resolvers = {
  Query: {
    hello: () => 'Hello world',
  },
  Mutation: {
    alexaHello: (_, { name }) => `Alexa: Hello world, ${name}`,
  },
}
const schema = makeExecutableSchema({ typeDefs, resolvers })

const transformedSchema = transformSchema(schema, {
  alexaHello: ({ args, resolve }) => resolve(args).replace('Bob', 'Alice'),
})

Overwrite arguments

const typeDefs = `
  type Query {
    hello: String!
  }

  type Mutation {
    alexaHello(name: String!): String!
  }
`
const resolvers = {
  Query: {
    hello: () => 'Hello world',
  },
  Mutation: {
    alexaHello: (_, { name }) => `Alexa: Hello world, ${name}`,
  },
}
const schema = makeExecutableSchema({ typeDefs, resolvers })

const transformedSchema = transformSchema(schema, {
  alexaHello: ({ args, resolve }) => resolve({ name: 'John' }),
})

Next steps

• Alias/rename types and fields
• Transform field arguments
• Compose new queries/mutations out of existing queries/mutations

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