@getstation/reactive-graphql
v4.0.3
Published
> GraphQL reactive executor
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Reactive GraphQL
GraphQL reactive executor
Execute GraphQL queries against reactive resolvers (resolvers that return Observable) to get a reactive results.
Install
$ npm i reactive-graphql --save
Usage
The usage is very similar to graphql-js
's graphql
function, except that:
- resolvers can return an Observable
- the result of a query is an Observable
import { graphql } from "reactive-graphql";
import { makeExecutableSchema } from "graphql-tools";
import { timer } from "rxjs";
const typeDefs = `
type Query {
time: Int!
}
`;
const resolvers = {
Query: {
// resolvers can return an Observable
time: () => {
// Observable that emits increasing numbers every 1 second
return timer(1000, 1000);
}
}
};
const schema = makeExecutableSchema({
typeDefs,
resolvers
});
const query = `
query {
time
}
`;
const stream = graphql(schema, query);
// stream is an Observable
stream.subscribe(res => console.log(res));
outputs
{ data: { time: 0 } }
{ data: { time: 1 } }
{ data: { time: 2 } }
{ data: { time: 3 } }
{ data: { time: 4 } }
...
Caveats
GraphQL Subscriptions are not supported (see issue #27) as everything is treated as subscriptions.
See Also
Advanced usage
import React from "react";
import ReactDOM from "react-dom";
import "./styles.css";
import { graphql } from "reactive-graphql";
import { makeExecutableSchema } from "graphql-tools";
import { from, interval, of } from "rxjs";
import { map, merge, scan, combineLatest } from "rxjs/operators";
import { componentFromStream } from "@dcos/data-service";
// mocked API clients that return Observables
const oldPosts = from(["my first post", "a second post"]);
const newPosts = interval(3000).pipe(map(v => `Blog Post #${v + 1}`));
const fetchPosts = () =>
oldPosts.pipe(
merge(newPosts),
scan((acc, item) => [...acc, item], [])
);
const votesStore = {};
const fetchVotesForPost = name => of(votesStore[name] || 0);
const schema = makeExecutableSchema({
typeDefs: `
type Post {
id: Int!
title: String!
votes: Int!
}
# the schema allows the following query:
type Query {
posts: [Post]
}
# this schema allows the following mutation:
type Mutation {
upvotePost (
postId: Int!
): Post
}
`,
resolvers: {
Query: {
posts(parent, args, context) {
return fetchPosts().pipe(
map(emittedValue =>
emittedValue.map((value, index) => ({ id: index, title: value }))
)
);
}
},
Post: {
votes(parent, args, context) {
return fetchVotesForPost(parent.title);
}
}
}
});
const query = `
query {
posts {
title
votes
}
}
`;
const postStream = graphql(schema, query);
const PostsList = componentFromStream(propsStream =>
propsStream.pipe(
combineLatest(postStream, (props, result) => {
const {
data: { posts }
} = result;
return posts.map(post => (
<div>
<h3>{post.title}</h3>
</div>
));
})
)
);
function App() {
return (
<div className="App">
<PostsList />
</div>
);
}
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);
License
Apache 2.0