https://github.com/killercodemonkey/graphql-pub-sub-with-initial-value

GraphQL PubSub with intial value handling
https://github.com/killercodemonkey/graphql-pub-sub-with-initial-value

apollo apollo-server graphql pubsub subscription

Last synced: 20 days ago
JSON representation

GraphQL PubSub with intial value handling

• Host: GitHub
• URL: https://github.com/killercodemonkey/graphql-pub-sub-with-initial-value
• Owner: KillerCodeMonkey
• License: mit
• Created: 2019-06-20T13:42:51.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2024-03-13T05:00:53.000Z (8 months ago)
• Last Synced: 2024-03-14T16:24:01.919Z (8 months ago)
• Topics: apollo, apollo-server, graphql, pubsub, subscription
• Language: TypeScript
• Size: 1.93 MB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 7
• Metadata Files:
  • Readme: README.md
  • Funding: .github/FUNDING.yml
  • License: LICENSE.MD

Awesome Lists containing this project

README

        
# graphql-pub-sub-with-initial-value

[![Build Status](https://github.com/KillerCodeMonkey/graphql-pub-sub-with-initial-value/workflows/CI/badge.svg)](https://github.com/KillerCodeMonkey/graphql-pub-sub-with-initial-value/actions/) [![codecov](https://codecov.io/gh/KillerCodeMonkey/datetime-periods/branch/master/graph/badge.svg)](https://codecov.io/gh/KillerCodeMonkey/graphql-pub-sub-with-initial-value)

GraphQLPupSubWithIntialValue is a simple npm package that extends GraphQLPubSub with an `asyncIteratorWithInitialState` method. It lets you define an async function how to get the initial value.

Additionally it provides the possibilty to execute some cleanup work, when a client disconnects or the AsynIterator is closed. For that you can use the exported `withCancel` or the `pubSub.withCancel` function.

For more information checkout the [GraphQL-Subscriptions](https://github.com/apollographql/graphql-subscriptions)

## Donate/Support

If you like my work, feel free to support it. Donations to the project are always welcomed :)



PayPal: [PayPal.Me/bengtler](http://paypal.me/bengtler)

### Installation

`npm install graphql-pub-sub-with-initial-value` or `yarn add graphql-pub-sub-with-initial-value`

> This package has peerDependencies to `"graphql": "^14.3.1 || ^15.3.0"` and `"graphql-subscriptions": "^1.1.0"`, which you have to install yourself.

### Usage

#### Easy & Simple

```TS

const asyncInititalValueFn = () => {

  // grab initial values somewhere else. Read from file, memory, 🤷

  return Promise.resolve(['test'])

}

import { PubSubWithIntialValue } from 'graphql-pub-sub-with-initial-value'

const pubSubWithInitialValue = new PubSubWithIntialValue()

const asyncIterator = pubSubWithInitialValue.asyncIteratorWithInitialValue('TOPIC', asyncInititalValueFn)

pubSubWithInitialValue.withCancel(asyncIterator, () => console.log('on close/disconnect'))

// triggers cancel/disconnect

asyncIterator.return()

```

#### In a resolver of subsciption (ApolloServer)

It is recommended to put the pubSub on the context object during the ApolloServer creation or use PubSubs in combination with datasources or create it in a seperated file to reuse the instance.

```TS

import { GraphQLList, GraphQLNonNull, GraphQLObjectType, GraphQLString } from 'graphql'

import { PubSubWithIntialValue } from 'graphql-pub-sub-with-initial-value'

export const subscription = new GraphQLObjectType({

  fields: {

    callings: {

      resolve(payload) {

        return payload

      },

      subscribe(_obj, _args, context: { pubSub: PubSubWithIntialValue }): AsyncIterable {

        return context.pubSub.asyncIteratorWithInitialValue(() => Promise.resolve(['test']))

      },

      type: GraphQLNonNull(GraphQLList(GraphQLNonNull(GraphQLString)))

    }

  },

  name: 'Subscription'

})

```