[Remix](https://remix.run) is a full-stack web framework that lets you focus on the user interface and work back through web fundamentals to deliver a fast, slick, and resilient user experience. This is what excited me when I first read about Remix. I'm a big advocate for progressively enhancing web applications and this framework seems to take this approach by simply using web fundamentals.

This is not a step-by-step guide on how to make a web application with Remix, but rather some features I noticed and wanted to highlight. That might come later. If you are looking for that, [Remix.run](http://Remix.run) is an amazing landing page and contains very well written documentation that will take you through all the reasons why they build this framework, what it offers and how it works. Seriously, one of the best landing pages I've seen in the past few years. Please, have a read there and come back for my view as a [Next.js](https://nextjs.org/) fanboy.
## Routing mechanism
Like Next.js, Remix uses a file-based routing system. In `/app` (where your app will live) you can create a folder called `routes`. Every file you add (e.g. `/app/routes/example` will create a route and page under `http://website.com/example`. If you're unfamiliar with this concept, please read my article [A simple, yet detailed introduction to Next.js](https://www.davebitter.com/articles/a-simple-yet-detailled-introduction-to-next-js). Next.js and Remix work nearly the same with some exceptions like creating a dynamic page (`[slug]` vs. `$slug`. If this is not the way you want to work, you can also define your routes in an object for both of these frameworks.
### Nested routes
Remix seems to heavily rely on the usage of nested routes as "partials". Let's say you are building an admin view. You might have multiple routes for several admin pages:
```
- app
    - routes
        - admin.tsx
        - admin
            - new.tsx
            - edit.tsx
                $user.tsx

```
All these admin pages might share a special navigation bar for logged in admins. Naturally, you could load a reusable component in the markup of all these pages, but that sounds more like a partial that you used to use back when building websites with templating languages like Pug or Handlebars. Remix allows you to just load the partial in `app/routes/admin.tsx` and add a Remix component called `<Outlet />` . This component serves as a placeholder where a child route can be rendered. In this case, that would be the new and edit route. I really like this approach of templating out pages.
### Scoped JS and CSS per nested route
These nested routes are not just useful as partials, but will allow Remix to also easily chunck-up your nested routes for JS and CSS bundles. Naturally, it knows what pieces to load as you load them per nested route. This makes these nested routes true small little routes and optimises the loading of resources.

This concept is fundamental to how Remix works. You can read more about nested routes [here](https://remix.run/docs/en/v1/guides/routing) and CSS scoping with `<Links />` [here](https://remix.run/docs/en/v1/guides/styling).
## Server- and client-side code
We've seen great strides by Next.js to make it easy for developers to expose server-side functions right next to client-side code. You can read more about that in my article [Next.js page generation](https://www.davebitter.com/articles/next-js-page-generation). At a first glance, Remix has an evenly convenient, if not better solution. I feel like Remix takes it to the next level by fully focussing on not having to use client-side JS as a standard, but rather an afterthought.
### Loaders
Many web applications need to fetch data. You can use `loader` functions in combination with a `useLoaderData` hook to set this up.
```jsx
import type { LoaderFunction } from "remix";
import type { User } from "@prisma/client";
import { db } from "~/utils/db.server";

type LoaderData = { users: Array<User> };
export let loader: LoaderFunction = async () => {
  const data: LoaderData = {
    users: await db.user.findMany()
  };

  return { data };
};

export default function Users() {
  const data = useLoaderData<LoaderData>();

  return (
    <ul>
      {data.map(user => (
        <li>{user.name}</li>
      ))}
    </ul>
  );
}
```
There is quite some Typescript-specific code here, but in its essence there is an async function exported called `loader`. This function fetches some data and returns an object with data. Note that you can return multiple pieces of data from various sources here. You can now access all this data using the `useLoaderData` hook. An important aspect of this is that no client-side JS is needed here. You just want some data from your server-side function and then use it to render a list on the server to serve to the client.
### Actions
So what about handling things like forms? I need to handle that on the client right? Well, not necessarily. Forms can easily be handled with a `method` attribute on the form element. Sure, you might want to make a fancy multi-step form, but this is where progressive enhancement pops up again. Just make a form with a `method` and let it post using the web standards. You then export an `action` function that will handle the posting of the form. Take a look at this code snippet of the [Jokes app tutorial](https://remix.run/docs/en/v1/tutorials/jokes) I followed in preparation for this article. You can find my full end result in [this repository](https://github.com/DaveBitter/remix-jokes).
```jsx
import type { ActionFunction } from "remix";
import { redirect } from "remix";
import { db } from "~/utils/db.server";

export const action: ActionFunction = async ({
  request
}) => {
  const form = await request.formData();
  const name = form.get("name");
  const content = form.get("content");
  // we do this type check to be extra sure and to make TypeScript happy
  // we'll explore validation next!
  if (
    typeof name !== "string" ||
    typeof content !== "string"
  ) {
    throw new Error(`Form not submitted correctly.`);
  }


  const fields = { name, content };


  const joke = await db.joke.create({ data: fields });
  return redirect(`/jokes/${joke.id}`);
};

export default function NewJokeRoute() {
  return (
    <div>
      <p>Add your own hilarious joke</p>
      <form method="post">
        <div>
          <label>
            Name: <input type="text" name="name" />
          </label>
        </div>
        <div>
          <label>
            Content: <textarea name="content" />
          </label>
        </div>
        <div>
          <button type="submit" className="button">
            Add
          </button>
        </div>
      </form>
    </div>
  );
}
```
There is a basic form (with no client-side JS) that just posts on submit. The `action` function is then called where we can then get the form data and handle it like normal. But what about validation? Naturally, you want to do this on the server, but it's considered good practice to do this on the client as well. The nice thing about having everything in this file is that we can reuse the same validation function in both places. Here's another snippet with just server-side validation implemented.
```jsx
import type { ActionFunction, LoaderFunction } from "remix";
import {
    useActionData,
    redirect,
    Form
} from "remix";
import { JokeDisplay } from "~/components/joke";
import { db } from "~/utils/db.server";
import {
    requireUserId,
    getUserId
} from "~/utils/session.server";

export const loader: LoaderFunction = async ({
    request
}) => {
    const userId = await getUserId(request);
    if (!userId) {
        throw new Response("Unauthorized", { status: 401 });
    }
    return {};
};

function validateJokeContent(content: string) {
    if (content.length < 10) {
        return `That joke is too short`;
    }
}

function validateJokeName(name: string) {
    if (name.length < 2) {
        return `That joke's name is too short`;
    }
}

type ActionData = {
    formError?: string;
    fieldErrors?: {
        name: string | undefined;
        content: string | undefined;
    };
    fields?: {
        name: string;
        content: string;
    };
};

export const action: ActionFunction = async ({
    request
}): Promise<Response | ActionData> => {
    const userId = await requireUserId(request);
    const form = await request.formData();
    const name = form.get("name");
    const content = form.get("content");
    if (
        typeof name !== "string" ||
        typeof content !== "string"
    ) {
        return { formError: `Form not submitted correctly.` };
    }


    const fieldErrors = {
        name: validateJokeName(name),
        content: validateJokeContent(content)
    };
    const fields = { name, content };
    if (Object.values(fieldErrors).some(Boolean)) {
        return { fieldErrors, fields };
    }


    const joke = await db.joke.create({
        data: { ...fields, jokesterId: userId }
    });
    return redirect(`/jokes/${joke.id}`);
};

export default function NewJokeRoute() {
    const actionData = useActionData<
        ActionData | undefined
    >();


    return (
        <div>
            <p>Add your own hilarious joke</p>
            <Form method="post">
                <div>
                    <label>
                        Name:{" "}
                        <input
                            type="text"
                            defaultValue={actionData?.fields?.name}
                            name="name"
                            aria-invalid={
                                Boolean(actionData?.fieldErrors?.name) ||
                                undefined
                            }
                            aria-describedby={
                                actionData?.fieldErrors?.name
                                    ? "name-error"
                                    : undefined
                            }
                        />
                    </label>
                    {actionData?.fieldErrors?.name ? (
                        <p
                            className="form-validation-error"
                            role="alert"
                            id="name-error"
                        >
                            {actionData.fieldErrors.name}
                        </p>
                    ) : null}
                </div>
                <div>
                    <label>
                        Content:{" "}
                        <textarea
                            defaultValue={actionData?.fields?.content}
                            name="content"
                            aria-invalid={
                                Boolean(actionData?.fieldErrors?.content) ||
                                undefined
                            }
                            aria-describedby={
                                actionData?.fieldErrors?.content
                                    ? "content-error"
                                    : undefined
                            }
                        />
                    </label>
                    {actionData?.fieldErrors?.content ? (
                        <p
                            className="form-validation-error"
                            role="alert"
                            id="content-error"
                        >
                            {actionData.fieldErrors.content}
                        </p>
                    ) : null}
                </div>
                <div>
                    <button type="submit" className="button">
                        Add
                    </button>
                </div>
            </Form>
        </div>
    );
}
```
Note that we return the validation messages if there is something wrong and render the page again accessing them with the `useActionData` hook. If the form validates fine, we can redirect to the overview page.
> This is a great example of how easy it can be to create an interactive part of your web application without the need for client-side JS for something that has web standards. Sure you can, but Remix is built in a way where you take this approach first.

## Resource routes
If I would've build the previous form without any client-side JS in Next.js, I would've had to build a Next.js API route. These are incredibly powerful. You can read more about these API routes in my article [Next.js API routes](https://www.davebitter.com/articles/next-js-api-routes). With Remix, you can do exactly the same, but even more. Remix doesn't just offer this for, for instance, JSON responses, but for any kind of response really. You can create a file with a special naming pattern like `/app/routes/jokes[.]rss.tsx`. The `[.]rss` part tells Remix that you will return a `.rss` file. In this code snippet, you can see how something like this could work.
```jsx
import type { LoaderFunction } from "remix";
import { db } from "~/utils/db.server";

export const loader: LoaderFunction = async ({
    request
}) => {
    const jokes = await db.joke.findMany({
        take: 100,
        orderBy: { createdAt: "desc" },
        include: { jokester: { select: { username: true } } }
    });


    const host =
        request.headers.get("X-Forwarded-Host") ??
        request.headers.get("host");
    if (!host) {
        throw new Error("Could not determine domain URL.");
    }
    const protocol = host.includes("localhost")
        ? "http"
        : "https";
    const domain = `${protocol}://${host}`;
    const jokesUrl = `${domain}/jokes`;


    const rssString = `
    <rss xmlns:blogChannel="${jokesUrl}" version="2.0">
      <channel>
        <title>Remix Jokes</title>
        <link>${jokesUrl}</link>
        <description>Some funny jokes</description>
        <language>en-us</language>
        <generator>Kody the Koala</generator>
        <ttl>40</ttl>
        ${jokes
            .map(joke =>
                `
            <item>
              <title>${joke.name}</title>
              <description>A funny joke called ${joke.name}</description>
              <author>${joke.jokester.username}</author>
              <pubDate>${joke.createdAt}</pubDate>
              <link>${jokesUrl}/${joke.id}</link>
              <guid>${jokesUrl}/${joke.id}</guid>
            </item>
          `.trim()
            )
            .join("\n")}
      </channel>
    </rss>
  `.trim();


    return new Response(rssString, {
        headers: {
            "Cache-Control": `public, max-age=${60 * 10
                }, s-maxage=${60 * 60 * 24}`,
            "Content-Type": "application/xml",
            "Content-Length": String(Buffer.byteLength(rssString))
        }
    });
};
```
How cool is that! The routes folder is not just for HTML pages, but you can create routes for any resource you need, hence the name resource routes.
## Nested route utility exports
I found the utility exports that Remix offers on nested routes incredibly nice to use. Previously, I mentioned you could import CSS on nested routes and have it scoped and chuncked to just that nested route. There are a variety of other Remix utilities you can use scoped to a nested route.
### SEO
You probably want to add some meta-tags to your pages. You can do this easily by exporting a `MetaFunction` on (nested) routes. Let's say you have some basic meta-tags on the root of the pages under `app/root.tsx`. You can export that function there like so:
```jsx export const meta: MetaFunction = () => {

  const description = `Learn Remix and laugh at the same time!`;
  return {
    description,
    keywords: "Remix,jokes",
    "twitter:image": "https://remix-jokes.lol/social.png",
    "twitter:card": "summary_large_image",
    "twitter:creator": "@remix_run",
    "twitter:site": "@remix_run",
    "twitter:title": "Remix Jokes",
    "twitter:description": description
  };
};
```
But you might want to update the title or description for a specific nested route. You guessed it, you can export the same function with different values there to extend this base set of meta tags. I think that's pretty sweet.
### Error handling
You can export a `CatchBoundary` and `ErrorBoundary` function for every (nested) route.
```jsx
export function CatchBoundary() {
    const caught = useCatch();


    if (caught.status === 404) {
        return (
            <div className="error-container">
                There are no jokes to display.
            </div>
        );
    }
    throw new Error(
        `Unexpected caught response with status: ${caught.status}`
    );
}

export function ErrorBoundary() {
    return (
        <div className="error-container">
            I did a whoopsies.
        </div>
    );
}
```
This will help you with two things. You can notify the user with some custom message on the page, but more importantly, you can isolate this error to just the nested route. The rest of you're application will run fine. This helps you think about how you want to handle your not so optimal flow.
## Finally, loading some client-side JS for the first time
During the Jokes app tutorial, I didn't even realize that hadn't written any client-side JS yet. I think it's really cool that Remix doesn't load any client-side JS by default. Naturally, you might need some client-side JS so you can load the `<Scripts />` component. This is the first time you will see JS files in your network tab. These optimised and chuncked files will be loaded and "hydrate" your application on the client.
## Verdict.
I'm a big advocate of Progressive Enhancement to make web applications simple, accessible and resilient. You can read some of my articles on this [here](https://www.davebitter.com/tags/progressive-enhancement). I usually put this to practice for just components. Seeing Remix take this approach to the entire application gives me hope for a future of building great web applications using web standards and progressive enhancement.

For the first time in years, I felt like a "web developer" again instead of a JS engineer. It's incredible fun to start thinking about how to leverage these standards smartly. I'm very excited about what Remix will offer and will definitely continue researching Remix and sharing it with all of you. Thanks for reading!

First look at Remix

## The issue with SEO in SPAs
The issue with SEO in SPAs has to do with where the page gets built or rendered. The rise of client-side SPA frameworks like [React.js](https://reactjs.org/), [Vue.js](https://vuejs.org/) and others caused an issue I didn't encounter before with server-side frameworks.
In short, there are two ways of rendering a page. Traditionally, the page gets rendered on the server. As a result, bots like [GoogleBot](https://yoast.com/what-is-googlebot/) will visit your page, read the content and [meta tags](https://www.webpresencesolutions.net/metadata-meta-tags-web-page-titles-page-descriptions-explained/) of the page and use that information for Googles search engine. SPA frameworks work a little different. Normally, a blank page is loaded. The framework will build the entire page client-side as soon as the JavaScript bundle is loaded. Besides potential performance issues, this raised a new problem. Bots will visit a page, find a blank page and return that information.
## So is Google just ignoring this?
Nope, they are trying their best to deal with this issue. As you can read [here](https://webmasters.googleblog.com/2014/05/understanding-web-pages-better.html), Google can execute JavaScript to build the page and then get the content and metadata. So, problem fixed? Well, not entirely. They mention that _sometimes things don't go perfectly during rendering, which may negatively impact search results for your site_. Google is providing tools for you to debug and see what causes issues.
> Building applications for the web is hard enough.
## Do I want to deal with this?
Well, no. Building applications for the web is hard enough. At the start, I mentioned that I wanted to solve this issue with modern tools and techniques I love to use. Let's pick React.js as the SPA framework. I love to use React.js in combination with [Next.js](https://nextjs.org/) to solve many of the issues with SPA frameworks. You can read up on that in my article on [Implementing the latest web technologies to boost the Mirabeau blog](/articles/mirabeau-blog-latest-web-technologies).
![React.js and Next.js](//images.ctfassets.net/w4dg3cjf42ew/5JdNrYGW2SBKmIoT38kqz0/80b019ca3d6e00871b3603f842814b0c/CDFEF415-123A-4D0E-85AD-BB3B32A0B3A1-min.png)*React.js and Next.js working together*

I will leverage the solution that Next.js offers regarding server-side rendering. This solves the issue in the old fashioned way. The page will be rendered on the server, GoogleBot will get the content and metadata and I will have solved my problem.
## Taking it a bit further
I can call it a day now, but let's look at how I took it a bit further when building the  the [Mirabeau blog](blog.mirabeau.nl). The content, [semantically written](https://html.com/semantic-markup/), is received by the GoogleBot. The metadata implementation needs to be done by me. In theory, it is simple. I have a set of [basic meta tags](https://support.google.com/webmasters/answer/79812?hl=en) that I update for every page. An article page may use the title and description of the article while the home page uses the name of the blog and the tagline.
In the case of Next.js, I load a component called `SiteMeta` the head element of the page using the Next.js `head` component like so:
![Simplified code snippet of loading SiteMeta component](//images.ctfassets.net/w4dg3cjf42ew/1ux4A6clBzDNpDdqYdoc7I/a8cd4433d13cb83b6e822f057bd2a968/meta-tags.png)*Simplified code snippet of loading SiteMeta component*
For an article, for instance, I set the title tag to the title of the article. I then load the `SiteMeta` component that sets a couple more tags. This is already starting to look more like it. The meta tags are being added dynamically based on the article and locale. Here you can see a simplified version:
![Simplified code snippet of SiteMeta component](//images.ctfassets.net/w4dg3cjf42ew/4RkWDgVEekZ7QlDK2CxE6A/7a00962575163a0ebadabbbdcf3418f1/site-meta.png)*Simplified code snippet of SiteMeta component*
## Taking it even further by taking social media into account
Social media is vital for the reach of your blog. Naturally, we need to spend some time here to have the best chance of getting people to click the link to the article.
### OpenGraph
I can specify the page even further by using standards with [Open Graph](https://ogp.me/). It’s a protocol that is widely supported by all major social media websites and crawlers. I use Open Graph to create semantical tags for SEO and sharing. For example, I can provide a title, image and summary for an article page specifically aimed towards social media sites. I now load a second component called `SiteOpenGraphTags` in the head element.
![Simplified code snippet of loading OpenGraphTags component](//images.ctfassets.net/w4dg3cjf42ew/7b71NBLQBlK5VK9x0nPcEn/36b05ab8de8b8ed3b10078f091bd2e87/open-graph-tags.png)*Simplified code snippet of loading OpenGraphTags component*
Here we can set additional tags according to the Open Graph specification. Below you find a simplified version that for instance sets tags specific for [Twitter cards](https://developer.twitter.com/en/docs/tweets/optimize-with-cards/guides/getting-started).
![Simplified code snippet of OpenGraphTags component](//images.ctfassets.net/w4dg3cjf42ew/6RHSmvijxYUhoyYCaBMysX/9bf84bed3b1183bb029536532b786bf2/site-open-graph.png)*Simplified code snippet of OpenGraphTags component*
## The result
When I share an article to social media I can now see that it shows a custom title, description and image that I can set in the CMS used. A social media card might look something like:
![Mirabeau blog social card example](//images.ctfassets.net/w4dg3cjf42ew/6tAjqUcClkipkwktwCRzhY/3252230919b7c43d4070cf55adccea10/mira-blog-seo.jpg)*Mirabeau blog social card example*
## Case: Lely Used
Sure, a blog is relatively simple. Often, we need to put in a bit more work. [Lely used](https://used.lely.com/en/why-used) is a platform I build similarly. The platform consists of 'content pages', a product search page and product detail pages. The goal is to sell products. As a result, detail pages are often shared on social media platforms. The implementation for many of the pages is the same, but as an article page on a blog, there is a product page on an e-commerce platform. I looked into setting dynamic tags specific to a product. Below you can see the response of a product detail page.
![Lely Used social card example](//images.ctfassets.net/w4dg3cjf42ew/2SsaB4tQB3QXMmenbqmonb/9249a5987f901dbe43df60740484307d/lely-used-seo.jpg)*Lely Used social card example*
I've added quite a bit of information in this card. You can see the:
- platform
- model
- location
- build-year
- localised currency and amount (price)
- specifications
- image of product
- content localised based on locale in link
These tags are being used both for sharing the product and by bots like GoogleBot.
## Looking back
SPA frameworks have an impact on SEO. Although Google is working hard an this, there are still several issues. I can solve all issues by using server-side rendering with a framework like Next.js. I can use React.js to dynamically load regular meta tags and Open Graph tags in the head element of the page. I can then fully customise the tags based on the what kind of page it is. This is my current way of handling SEO with SPA frameworks. What is yours?

How can I handle SEO in my Single-page application?

I am a Senior Front-end Consultant, Developer Advocate, and Google Developer Expert for Web. Here, you can find my resume, a collection of my articles covering a wide range of topics and get in contact.

Going for React.js can introduce quite a few new challenges like server-side render support, performance, SEO and more. In this talk, I go over how I solve those challenges by using Next.js, "The React Framework for Production" to progressively enhance your SPA.

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