FeaturesRealtime

React hooks / Next.js TypeScript SDK v3.32.0+

Realtime provides a useInngestSubscription() React hook, offering a fully typed experience for subscribing to channels.

useInngestSubscription() securely subscribes to channels using a subscription token fetched from the server.

In Next.js, this is implemented as a server action that returns a token, which is then used by the client to subscribe:

src/actions.ts

"use server";
// securely fetch an Inngest Realtime subscription token from the server as a server action
export async function fetchSubscriptionToken(): Promise<Realtime.Token<typeof helloChannel, ["logs"]>> {
  const token = await getSubscriptionToken(getInngestApp(), {
    channel: helloChannel(),
    topics: ["logs"],
  });

  return token;
}

src/App.tsx

"use client";

import { useInngestSubscription } from "@inngest/realtime/hooks";
import { getSubscriptionToken, Realtime } from "@inngest/realtime";
import { getInngestApp } from "@/inngest";
import { helloChannel } from "@/inngest/functions/helloWorld";
// import the server action to securely fetch the Realtime subscription token
import { fetchRealtimeSubscriptionToken } from "./actions";

export default function Home() {
  // subscribe to the hello-world channel via the subscription token
  // `data` is fully typed based on the selected channel and topics!
  const { data, error } = useInngestSubscription({
    refreshToken: fetchRealtimeSubscriptionToken,
  });

  return (
    <div>
      <h1>Realtime</h1>
      {data.map((message, i) => (
        <div key={i}>{message.data}</div>
      ))}
    </div>
  )
}

useInngestSubscription() API Reference

Parameters

  • enabled?: boolean - Whether or not the hook will subscribe.
  • bufferInterval?: number - If set and above 0, the outputs will only update every n milliseconds. This helps with very busy streams that could overwhelm a UI.
  • token?: Realtime.Subscribe.Token - The token to be used for subscribing (see Subscribe from the client).
  • refreshToken?: () => Promise<Realtime.Subscribe.Token> - A function that will be called if no token is available, or if the hook has been re-enabled and the previous token has expired.

A token or refreshToken parameter is required.

Return value

  • data: Array<Realtime.Message> - All messages received on the subscription in chronological order.
  • latestData: Realtime.Message - A shortcut to the last message received on the subscription. Useful for streams where each message is the latest state of an entity.
  • freshData: Array<Realtime.Message> - If bufferInterval is active, this will be the last batch of messages released from the buffer. If bufferInterval is inactive, this is always the latest message.
  • error: Error | null - If truthy, this indicates an error with the subscription.
  • state: InngestSubscriptionState - The current state of the subscription, one of "closed", "error", "refresh_token", "connecting", "active", or "closing".

Examples

useInngestSubscription() Next.js demo

Clone this demo to see an interactive example of the useInngestSubscription() hook in action.

Explore patterns and examples

Use Realtime to stream updates from one or multiple Inngest functions, or to implement a Human-in-the-Loop mechanism.