@nerjs/gql

Gql (apollo) config and utils

Install

npm i @nerjs/gql

or:

yarn add @nerjs/gql

Use

createClient()

create Apollo client.

const createClient = require('@nerjs/gql/client')
// or
import createClient from '@nerjs/gql/client'


const client = createClient({/* ...clientOptions */})

clientOptions

prop name	type	required	description
uri	String	✅	Graphql server endpoint. Used in HttpLink
httpOptions	Object		Other options HttpLink
wsUri	String		Graphql server websocket endpoint. Used in WebSocketLink
wsOptions	Object		Other otions WebSocketLink
links	Array		Array of ApolloLinks
onError	Function		errorHandler for apollo-link-error

createGqlServer

create ApolloServer

const createGqlServer = require('@nerjs/gql/server')

const server = createGqlServer({/* ...serverOptions */})

serverOptions

prop name	type	required	description
app	Application	✅	Express application
path	String	✅	Graphql uri endpoint
playground	Boolean		Enable graphql playground
types	String	✅	Path to graphql types. Used by merge-graphql-schemas
resolvers	String	✅	Path to graphql resolvers. Used by merge-graphql-schemas
middlewares	Array(Function | Object)		graphql-middleware
cors
formatError
context
subscriptions

GqlProvider

React component. Wrap over ApolloProvider.

const GqlProvider = require('@nerjs/gql/provider')
// or
import GqlProvider from '@nerjs/gql/provider'
import React from 'react'


const App = () => {
    return <GqlProvider {.../* providerProps */} />
}

providerProps

1. client: (ApolloClient): Required if not use clientOptions

or:

2. {...options} clientOptions

useGqlErrors

const useGqlErrors = require('@nerjs/gql/useGqlErrors')
// or
import useGqlErrors from '@nerjs/gql/useGqlErrors'

const { lastError } = useGqlErrors()

Returns the last error Does not work outside the GqlProvider or when using the first option

---

Scalars (resolvers)

const { ...scalars } = require('@nerjs/gql/scalars')

• DateResolver (scalar Date)
• NumberResolver (scalar Number)

gql middlewares

const { ...middlewares } = require('@nerjs/gql/mdw')

validate middleware

const validateMiddleware = require('@nerjs/gql/mdw/validate')


const schemaMiddlewares = {
    Query: {
        getItem: validateMiddleware({ input: yupInputSchema }),
        getItems: validateMiddleware(yupInputSchema)
    }
}

Used yup validation default errorWrapper YupGqlError

Custom (not yup) validation

The schema must have a .validate(input) method

const { createValidateMiddleware } = require('@nerjs/gql/mdw/validate')

const validateMiddleware = createValidateMiddleware({
    isSchemaField: '__isYupSchema__', // The property of an object, by which it is clear that this is a validator scheme
    schemaOptions: { abortEarly: false },
    errorWrapper: Error
})

notNull middleware

Prevents return NULL

const notNullMiddleware = require('@nerjs/gql/mdw/notNull')

const schemaMiddlewares = {
    User: {
        getUser: notNullMiddleware('User not found' /* error message */)
    }
}

throw NotFoundGqlError(message) if resolver return null

onlyId middleware

Prevents unnecessary resolver calls

const onlyIdMiddleware = require('@nerjs/gql/mdw/onlyId')

const schemaMiddlewares = {
    Post: {
        author: onlyIdMiddleware()
    }
}

returnBoolean middleware

Returns a boolean value depending on the success of the resolver. If preventError is specified as true - returns false instead of an exception

const returnBooleanMiddleware = require('@nerjs/gql/mdw/returnBoolean')

const schemaMiddlewares = {
    Post: {
        author: onlyIdMiddleware(/* preventError = false */)
    }
}

combine middlewares

Combines and launches middlewares

const combineMiddlewares = require('@nerjs/gql/mdw/combine')

const schemaMiddlewares = {
    Post: {
        author: combine(
            onlyIdMiddleware(),
            notNullMiddleware('Not foud author')
        )
    }
}

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🔗 All utils