Store data in a cookie with sessions and Remix

In the last article, we looked at creating a simple cookie in Remix to determine whether the user was visiting for the first time, or a returning regular. This is great for boolean logic — where they either have or haven’t visited before — but if we want to store additional data in our cookie, we will need a session.

Let’s modify our previous example to not only track whether this is the user’s first time on the page, but count how many times they have visited. For this we are going to use Remix’s createCookieSessionStorage function. Create a new file at app/utils/count-session.tsx and populate with the following:

import { createCookieSessionStorage } from "@remix-run/node";

export const { getSession, commitSession, destroySession } =
  createCookieSessionStorage({
    cookie: {
      name: "count-session",
    },
  });

createCookieSessionStorage returns three functions for managing our session:

• getSession retrieves a session from a cookie string
• commitSession creates a new cookie string
• destroySession deletes session data and returns a cookie string

Let’s also create a new page at app/routes/count.tsx and add the following:

import { json } from "@remix-run/node";
import { useLoaderData } from "@remix-run/react";
import { getSession, commitSession } from "~/utils/count-session";

export const loader = async ({ request }: { request: Request }) => {
  
}

const Count = () => {
  const data = useLoaderData();
  return <pre>{JSON.stringify(data, null, 2)}</pre>;
};

export default Count;

In our loader function we want to:

1. Read the session from the cookie headers
2. Increment by 1 if exists, otherwise set to 1
3. Create a new cookie string
4. Return new value as response with updated cookie in headers

The full component should look something like this:

import { json } from "@remix-run/node";
import { useLoaderData } from "@remix-run/react";
import { getSession, commitSession } from "~/utils/count-session";

export const loader = async ({ request }: { request: Request }) => {
  // Read session from cookie
  const session = await getSession(request.headers.get("Cookie"));

  // Increment by 1 if exists, otherwise set to 1
  const numberOfVisits: number = session.get("numberOfVisits") + 1 || 1;

  // Create new cookie string
  session.set("numberOfVisits", numberOfVisits);
  const cookie = await commitSession(session);

  // Set new cookie in headers
  return json(
    { numberOfVisits },
    {
      headers: {
        "Set-Cookie": cookie,
      },
    }
  );
}

const Count = () => {
  const data = useLoaderData();
  return <pre>{JSON.stringify(data, null, 2)}</pre>;
};

export default Count;

And that’s it! 🎉

If you navigate to http://localhost:3000/count and refresh a few times you should see the numberOfVisits value incrementing by 1 each time.

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