Getting started with Remix

What is Remix?
Remix is a relatively "new" React framework which was open sourced on 23rd of November 2021. It was originally created by the awesome Ryan Florence and Michael Jackson, and with the recent addition of Kent C. Dodds it allows the framework to sell itself more.

As per their website

Remix is a full stack web framework that let’s you focus on the user interface and work back through web fundamentals to deliver a fast, slick, and resilient user experience.

Let's get started with the actual coding.
Create a basic Remix app
Prerequisites
  • Make sure you have node installed
  • Basic understanding of React
  • Basic cli knowledge
  • Installation
    npx create-remix@latest
    # follow the prompts
    cd [whatever you named the project]

    NOTE: There will be an option to run npm install to install the dependencies immediately.
    This will create a package-lock.json. If you want to use yarn, you can skip this step, but don't forget to run yarn install later.

    Running the app

    Based on what you choose in the image below, a custom README.md file is created at the project's root.
    Make sure to check the steps on how to run the application locally

    Running examples

    You can use yarn for the steps below if you prefer

    For Remix App Server
    npm run dev
    For Express Server
    # Start the Remix development asset server
    $ npm run dev
    
    # In a new tab start your express app:
    npm run start:dev
    You should see something like this:
    If you don't, make sure to check README.md for specific instructions on how to run the app locally,

    I will be using TypeScript for this blog; if you prefer to use vanilla JavaScript, remove the type usages and change the extensions from .tsx to .jsx.

    Cleaning up
    Let's start coding with a clean slate.
    # Remove demo files
    rm -rf app/routes/demos app/styles/demos
    
    # We'll recreate this files later
    rm app/routes/index.tsx app/root.tsx
    Create a file named root.tsx file under app folder.
    Let's proceed with the mandatory hello world example.
    // app/root.tsx
    export default function App() {
      return (
        <html lang="en">
          <head>
            <meta charSet="utf-8" />
          </head>
          <body>
            <h2>Hello World</h2>
          </body>
        </html>
      );
    }
    Hello World, indeed.
    Since this file will serve as the global container for the app, let's refactor it to make this more generic.
    // app/root.tsx
    import {Links,LiveReload,Meta,Outlet,Scripts,ScrollRestoration} from "remix";
    
    export default function App() {
      return (
        <Document>
          <Layout>
            <Outlet />
          </Layout>
        </Document>
      );
    }
    
    // Here is the blueprint of our document
    // It looks like our typical HTML but with a few extra tags
    // I will discuss in another blog post those Components coming from the remix package
    function Document({
      children,
      title,
    }: {
      children: React.ReactNode;
      title?: string;
    }) {
      return (
        <html lang="en">
          <head>
            <meta charSet="utf-8" />
            <meta name="viewport" content="width=device-width,initial-scale=1" />
            {title ? <title>{title}</title> : null}
            <Meta />
            <Links />
          </head>
          <body>
            {children}
            <ScrollRestoration />
            <Scripts />
            {process.env.NODE_ENV === "development" && <LiveReload />}
          </body>
        </html>
      );
    }
    
    // Layout is a wrapper component that provides a consistent layout for all pages.
    function Layout({ children }: React.PropsWithChildren<{}>) {
      return <main>{children}</main>;
    }
    Create the index route file index.tsx under app/routes folder.
    Now, extract the content of our page
    // app/routes/index.jsx
    
    export default function Index() {
      return <div>
        <h2>Hello World</h2>
      </div>
    }
    The two changes above will still yield the same result:
    Create a link
    We'll add the links inside Layout since it will be reusable across all pages.
    // app/root.tsx
    import {Link /*other import*/} from "remix";
    // ...
    function Layout({children}: React.PropsWithChildren<{}>) {
      return (
        <>
          <header>
            <nav>
              <ul>
                <li>
                  <Link to="/vocab">Vocab</Link>
                </li>
              </ul>
            </nav>
          </header>
          <main>{children}</main>;
        </>
      );
    }
    // ...
    Result:
    After clicking the link or navigating to the URL, you should see something like this:
    It is expected since we have not created a route handler for the /pokemons page.
    Before creating that route, let us use CatchBoundary and useCatch to create a custom 404 error message as a fallback for all Not Found routes.
    // app/root.tsx
    import { useCatch /*other imports*/ } from "remix";
    // ...
    export function CatchBoundary() {
      let caught = useCatch();
    
      let message;
      switch (caught.status) {
        case 404:
          message = <p>This is a custom error message for 404 pages</p>
          break;
        // You can customize the behavior for other status codes
        default:
          throw new Error(caught.data || caught.statusText);
      }
    
      return (
        <Document title={`${caught.status} ${caught.statusText}`}>
          <Layout>
            <h1>
              {caught.status}: {caught.statusText}
            </h1>
            {message}
          </Layout>
        </Document>
      );
    }
    // ...
    Here is the customized 404 error page:

    This is one of Remix's magics; by simply following a convention, we can simplify common use cases.
    In the above case, we exported a function named CatchBoundary where we used useCatch inside to get a context about the error.
    Remix will do the heavy lifting; we simply need to adhere to, let's call it, a "contract function".

    To fix this 404 error, let's create the /pokemons route
    // app/routes/pokemons/index.tsx
    
    export default function Pokemons() {
      return (
        <div>
          <h2>Pokemons</h2>
        </div>
      );
    }
    Adding meta tags
    Meta tags are used here to update the title and description of the page. To learn more what meta is used for, check this
    // app/routes/pokemons/index.tsx
    
    // This is another "contract function"
    export function meta() {
      return {
        title: 'Pokemons',
        description: 'List of Pokemons',
      }
    }
    
    // export default function Pokemons...
    We should see an updated head
    Fetching Data
    Unlike the vanilla React where usually fetch the data from the client-side, in Remix we can load data from the server using a the concept of a loader
    Create a Loader
    // app/routes/pokemons/index.tsx
    import type { LoaderFunction } from "remix"
    
    // This is another "contract function"
    export const loader: LoaderFunction = () => {
      return fetch("https://pokeapi.co/api/v2/pokemon")
    }
    
    // export default function Pokemons...
    If you are wondering where is the .then(res => res.json()) part, you are not alone. I'm still cheking how they allow this magic to happen.

    NOTE: At the time of this writing, I don't know why there will be an error going back and forth on the pokemons listing page.
    As per reason, I will still append the .then(res => res.json()) to the loader function.

    Accessing data in React
    Use the useLoaderData hook to access the data in React land.
    // app/routes/pokemons/index.tsx
    import { useLoaderData, Link /*other imports*/ } from 'remix'
    
    // export let loader: LoaderFunction...
    
    export default function Pokemons() {
      const data = useLoaderData()
    
      // Try to use console.log here
    
      return (
        <div>
          <h2>Pokemons</h2>
          <ul>
            {data.results.map(pokemon => (
              <li key={pokemon.name}>
                <Link to={`/pokemons/${pokemon.name}`}>{pokemon.name}</Link>
              </li>
            ))}
          </ul>
        </div>
      )
    }
    Combining the two previous codes will result to:
    Creating a dynamic route
    For this demo, let's use the file path convention.
    Under the pokemons folder, create a folder named $pokemonName.tsx.
    Yes, it's not a typo; add a $ before the file name. We'll see how to use it later.
    // app/routes/pokemons/$pokemonName.tsx
    
    export default function Pokemon() {
      return (
        <div>
          <h1>Specific Pokemon Route</h1>
        </div>
      );
    }
    If we click bulbasaur in the list, we should see something like this:
    Now, how do we customize the page to show the details of a Pokemon?
    By naming the file $pokemonName.tsx, inside the file, we can access pokemonName inside the params object.
    We can use this information to fetch the specific data from the server. see line #9
    // app/routes/pokemons/$pokemonName.tsx
    import { useLoaderData } from "remix"
    import type { LoaderFunction } from "remix"
    
    export let loader: LoaderFunction = async ({ params }) => {
      const pokemonName = params.pokemonName;
      // OR const { pokemonName } = params;
    
      const details = await fetch(
        `https://pokeapi.co/api/v2/pokemon/${pokemonName}`
      ).then((res) => res.json());
    
      // We'll map the data based on our needs
      return {
        name: pokemonName,
        weight: details.weight,
        img: details.sprites.front_default,
        id: details.id,
      };
    };
    
    export default function Pokemon() {
      const pokemon = useLoaderData();
    
      return (
        <div>
          <h1>
            {pokemon.name} #{pokemon.id}
          </h1>
          <img src={pokemon.img} alt={pokemon.name} />
          <p>Weight: {pokemon.weight}</p>
        </div>
      );
    }
    With the code above, we can show these details in our page
    Update meta of pokemon route
    Before wrapping this up, let's update the meta of the Pokemon details page.
    // app/routes/pokemons/$pokemonName.tsx
    import type { MetaFunction } from "remix"
    
    // You can access the `loader` data here
    export const meta: MetaFunction = ({ data }) => {
      return {
        title: `#${data.id} ${data.name}`,
        description: `Details of ${data.name}`,
      };
    }
    And here is a page with a better title and description
    Putting all the codes together
    Link to the source
    Here's a demo
    Conclusion
    This is still a pretty small application for me to assess what Remix can do, and I have not even gotten into one of their selling points, the Nested Routes.nBut, so far, I like how easy it is to create an application from scratch, and I find the convention easy to follow. I also like how they provide hooks to more conveniently work with the data, errors, etc. Having said that, I definitely will explore more
    about Remix and the ecosystem in the future.
    What's next?
  • Styling
  • Nested Routing
  • Form Handling
  • SEO
  • MDX
  • Testing
  • Configuration
  • Deployment
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    Getting started with Remix