herbs2gql

herbs2gql creates GraphQL types based on herbs entities (gotu) and usecases (buchu), based on Apollo GraphQL.

Installing

$ npm install @herbsjs/herbs2gql

Using

All methods returns a string in GraphQL format representing the type based (gql) and a resolver (when expected).

Herbarium integration

If your project uses Herbarium as discovery service you can use herbs2gql with less code:

const { herbarium } = require('@herbsjs/herbarium')
const { herbs2gql } = require('@herbsjs/herbs2gql')

const { mutations, queries, types } = herbs2gql(herbarium)

GraphQL Type

To convert a Herbs Entity to GraphQL Type:

const { entity2type } = require('@herbsjs/herbs2gql')

const entity = entity('User', {
    id: field(String),
    name: field(String),
    document: field(String),
    age: field(Number),
    active: field(Boolean),
})

const gql = entity2type(entity)

GraphQL Input

To convert a Herbs Entity to GraphQL Input:

const { entity2input } = require('@herbsjs/herbs2gql')

const entity = entity('UserFilter', {    
    name: field(String),    
    age: field(Number),    
})

const gql = entity2input(entity)

GraphQL Query

To convert a Herbs Use Case to GraphQL Query:

const { usecase2query } = require('@herbsjs/herbs2gql')

const usecase = usecase('Get User', {
    request: {
        id: Number,
        document: String
    },

    response: User
})

const resolverFunc = (parent, args, context, info) => { }

const [gql, resolver] = usecase2query(usecase, resolverFunc)

GraphQL Mutation

To convert a Herbs Use Case to GraphQL Mutation:

const { usecase2mutation } = require('@herbsjs/herbs2gql')

const usecase = usecase('Update User', {
    request: {
        id: Number,
        name: String,
        age: Number,
        active: Boolean
    },

    response: User
})

const resolverFunc = (parent, args, context, info) => { }

const [gql, resolver] = usecase2mutation(usecase, resolverFunc)

GraphQL Subscription

To convert a Herbs Use Case to GraphQL Subscription:

const { usecase2subscription } = require('@herbsjs/herbs2gql')

const usecase = usecase('New User Notification', {
    request: {
        id: Number,        
    },

    response: UserMessage
})

const resolverFunc = () => { }

const [gql, resolver] = usecase2subscription(usecase, resolverFunc)

GraphQL Resolvers

herbs2gql provides a generic resolver implementation for mutations and queries.

const { defaultResolver } = require('@herbsjs/herbs2gql')

const updateUser = (injection) => usecase('Update User', {
    request: {
        id: Number,
        name: String,
        age: Number,
        active: Boolean
    },

    response: User
})

const [gql, resolver] = usecase2mutation(updateUser(), defaultResolver(updateUser))

In case you need to implement your own resolver:

const usecase = usecase('Update User', {
    request: {
        id: Number,
        name: String,
        age: Number,
        active: Boolean
    },

    response: User
})

const resolverFunc = (parent, args, context, info) => { }

const [gql, resolver] = usecase2mutation(usecase, resolverFunc)

Or you can use herbs2gql defaultResolver implementation as a reference.

Error Handling

herbs2gql deals with errors in the default resolver. It translates the usecase's errors into graphql errors:

Usecase Error	Apollo Error
Permission Denied	ForbiddenError
Not Found	ApolloError
Already Exists	ApolloError
Unknown	ApolloError
Invalid Arguments	UserInputError
Invalid Entity	UserInputError
Any other kind of errors	UserInputError

However, it's behavior can be overridden in the errorHandler property of the options parameter:

const { defaultResolver } = require('@herbsjs/herbs2gql')

const myCustomErrorHandler = (usecaseResponse) => {
    // handle the errors on your own way
}

const options = {
    errorHandler: myCustomErrorHandler
}

const updateUser = usecase('Update User', {
    // usecase implementation
})

const [gql, resolver] = usecase2mutation(updateUser(), defaultResolver(updateUser, options))

Your custom error handler can also utilize the defaultErrorHandler as a fallback:

const { defaultResolver, defaultErrorHandler } = require('@herbsjs/herbs2gql')

const myCustomErrorHandler = (usecaseResponse) => {
    // handle the errors on your own way

    // use the default error handler when there is no need of a specific treatment
    return defaultErrorHandler(usecaseResponse)
}

const options = {
    errorHandler: myCustomErrorHandler
}

const updateUser = usecase('Update User', {
    // usecase implementation
})

const [gql, resolver] = usecase2mutation(updateUser(), defaultResolver(updateUser, options))

Custom Names or Conventions

In Herbs it is possible to include personalized names for queries, mutations, inputs and types custom names are always prioritized

Custom Names

const options = { inputName: 'An-Entity' }

// for entity2input
const gql = entity2input(givenAnInput, options)

// for entity2type
const gql = entity2type(givenAnEntity, options)

//for mutation, query or subscription example using mutation
const [gql, resolver] = usecase2mutation(givenAnUseCase, resolverFunc, options)

Conventions

At the convention, a function must be sent, it must return a text formatted according to the sended convention

const options = { convention: { inputNameRule: (str) => `snake_case_returned` }}

// for entity2input
const gql = entity2input(givenAnInput, options)

// for entity2type
const gql = entity2type(givenAnEntity, options)

//for mutation, query or subscription example using mutation
const [gql, resolver] = usecase2mutation(givenAnUseCase, resolverFunc, options)

Apollo Errors and Err

Herbs2gql translates Herbs Known Errors to Apollo Errors as described in the documentation.

Example

Additionally you can view a simple demo application of this library in todolist-on-herbs.

How to contribute

If you would like to help contribute to this repository, please see CONTRIBUTING

License

MIT License

herbsjs/herbs2gql