Help with subscribe arguments

[ricardo-valero]

I'm probably doing something wrong, but how can I pass the subscribe GraphQL arguments root, args, context, info to an async generator?

This is a quick and silly example but has the pattern I follow: types, objects, field and async generator.

type RandomIntInput = {
  min: number
  max: number
  qty: number
}

const RandomIntInputObject = builder.inputRef<RandomIntInput>('RandomIntInput')

RandomIntInputObject.implement({
  fields: (t) => ({
    min: t.int(),
    max: t.int(),
    qty: t.int()
  })
})

builder.subscriptionField('randomInts', (t) =>
  t.field({
    type: 'Int',
    args: { input: t.arg({ type: RandomIntInputObject, required: true }) },
    subscribe: (root, { input }, context, info) => randomInts(input),
    resolve: async (payload: number) => payload
  })
)

async function* randomInts(input: RandomIntInput) {
  const { qty = 10, min = -10, max = 10 } = input // <- This always fails because it is undefined
  for (let i = 1; i <= qty; ++i) {
    await sleep(500)
    yield randomIntFromInterval(min, max)
  }
}

const sleep = (ms: number) => new Promise<void>((resolve) => setTimeout(resolve, ms))

const randomIntFromInterval = (min: number, max: number) => Math.floor(Math.random() * (max - min + 1) + min)

When I call the async generator the input is always undefined.
Any help is greatly appreciated.

[hayes]

I think there might be a bug with subscriptions. I haven't used them much myself. I'll get this fixed later today nevermind, my test set up was just slightly broken.

[hayes]

I suspect the issue is with how you are executing your query, or how the server is parsing/passing arguments. The following works for me, but if you have a more complete example, including how you are executing your subscription that might help.

import SchemaBuilder from "@pothos/core";
import { subscribe } from "graphql";
import gql from "graphql-tag";

const builder = new SchemaBuilder<{ DefaultInputFieldRequiredness: true }>({
  defaultInputFieldRequiredness: true,
});
type RandomIntInput = {
  min: number;
  max: number;
  qty: number;
};

const RandomIntInputObject = builder.inputRef<RandomIntInput>("RandomIntInput");

RandomIntInputObject.implement({
  fields: (t) => ({
    min: t.int(),
    max: t.int(),
    qty: t.int(),
  }),
});

const sleep = (ms: number) =>
  new Promise<void>((resolve) => setTimeout(resolve, ms));

const randomIntFromInterval = (min: number, max: number) =>
  Math.floor(Math.random() * (max - min + 1) + min);

async function* randomInts(input: RandomIntInput) {
  const { qty = 10, min = -10, max = 10 } = input;
  for (let i = 1; i <= qty; ++i) {
    await sleep(500);
    yield randomIntFromInterval(min, max);
  }
}

builder.queryType({
  fields: (t) => ({ hello: t.string({ resolve: () => "world" }) }),
});

builder.subscriptionType({});

builder.subscriptionField("randomInts", (t) =>
  t.field({
    type: "Int",
    args: { input: t.arg({ type: RandomIntInputObject, required: true }) },
    subscribe: (root, { input }, context, info) => randomInts(input),
    resolve: async (root: number) => {
      return root;
    },
  })
);

const schema = builder.toSchema({});

const result = subscribe({
  schema,
  document: gql`
    subscription {
      randomInts(input: { min: 1, max: 10, qty: 10 })
    }
  `,
});

result.then(async (itr) => {
  for await (const val of itr) {
    console.log(val.data.randomInts);
  }
});

I ran this with ts-node --transpile-only src/index.ts

and a tsconfig file with:

{
  "compilerOptions": {
    "strict": true,
    "module": "commonjs",
    "jsx": "preserve",
    "esModuleInterop": true,
    "sourceMap": true,
    "allowJs": true,
    "target": "es2021",
    "lib": [
      "es6",
      "dom"
    ],
    "rootDir": "src",
    "moduleResolution": "node"
  }
}

[ricardo-valero]

I'll compare it with mine. Thank you so much!

[ricardo-valero]

You were right it was how I was executing my query, it was a separate problem from pothos.
I removed graphql-jit from my GraphQL server and it worked.
Still not sure why, but again thanks!

[theogravity]

I have another subscription example here if anyone else needs it:

https://github.com/theogravity/graphql-pothos-server-example/tree/main/src/gql/subscriptions/posts