AddSchema

const {
    RenameTypes,
    transformSchema,
    introspectSchema,
    RenameRootFields,
    makeRemoteExecutableSchema
} = require('graphql-tools')
const fetch = require('node-fetch')
const { HttpLink } = require('apollo-link-http')

module.exports = async function ({
    addSchema, // gridsome api { addSchema }
    prefix, // new schema prefix
    uri // graphql source url
}) {

    const link = new HttpLink({
        uri,
        fetch,
        // headers: {}
    })

    const schema = await introspectSchema(link)

    const executableSchema = await makeRemoteExecutableSchema({ schema, link })

    const transformedSchema = transformSchema(
        executableSchema, [
            new RenameTypes( (type) => `${prefix}${type}` ),
            new RenameRootFields( (operation, name) => `${prefix}${name}` )
        ]
    )

    // Stitch transformed schema
    addSchema(transformedSchema)
}