graphql-js-no-tools-subscription.test.ts

import { GraphQLObjectType, GraphQLSchema, GraphQLString, parse, subscribe as gqlSubscribe } from "graphql";

function isAsyncIterable<T>(val: any): val is AsyncIterableIterator<T> {
  return val != null && typeof val[Symbol.asyncIterator] === "function";
}

const NodeType = new GraphQLObjectType({
  name: "Node",
  fields: {
    id: { type: GraphQLString }
  }
})

const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: "Query",
    fields: {
      node: {
        type: NodeType,
        resolve() {
          return { id: "" }
        }
      }
    }
  }),
  subscription: new GraphQLObjectType({
    name: "Subscription",
    fields: {
      nodes: {
        type: NodeType,
      //   resolve(source) {
      //    return source;
      //  },
        async *subscribe() {
          for (let i = 0; i < 3; i++) {
            yield {
              id: i.toString()
            };
          }
        },
      }
    }
  })
});

async function subscribe(query: string) {
  const document = parse(query);
  return gqlSubscribe({ document, schema })
}

describe("subscription happy case", () => {
  test("nodes and ids", async () => {
    const sub = await subscribe(`
      subscription {
        nodes {
          id
        }
      }
    `);
    if (isAsyncIterable(sub)) {
      let i = 0;
      for await (const val of sub) {
        expect(val.data?.nodes?.id).toBe((i++).toString());
      }
    }
  });
});

graphql-js-subscription.test.ts

import { makeExecutableSchema } from "@graphql-tools/schema";
import { parse, subscribe as gqlSubscribe } from "graphql";

function isAsyncIterable<T>(val: any): val is AsyncIterableIterator<T> {
  return val != null && typeof val[Symbol.asyncIterator] === "function";
}

const schema = makeExecutableSchema({
  typeDefs: `
    type Subscription {
      nodes: Node
    }
    type Query {
      node: String
    }
    type Node {
      id: ID
    }
  `,
  resolvers: {
    Query: {
      node: () => {
        return {
          id: ""
        }
      }
    },
    Subscription: {
      nodes: {
        async *subscribe() {
          for (let i = 0; i < 3; i++) {
            yield {
              id: i.toString()
            };
          }
        },
        /**
         * Without this resolver, the tests below would fail
         */
        // resolve(source) {
        //   return source;
        // }
      }
    }
  }
});

async function subscribe(query: string) {
  const document = parse(query);
  return gqlSubscribe({ document, schema })
}

describe("subscription happy case", () => {
  test("nodes and ids", async () => {
    const sub = await subscribe(`
      subscription {
        nodes {
          id
        }
      }
    `);
    if (isAsyncIterable(sub)) {
      let i = 0;
      for await (const val of sub) {
        expect(val.data?.nodes?.id).toBe((i++).toString());
      }
    }
  });
});