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Express in React! React Backend! Whut?! 🤯

Orkhan Jafarov on February 07, 2021

Hey there! One more implemented crazy idea for React Idea So, long time ago when I was researching react custom renderer, I had a crazy...

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Myzel394 • Feb 7 '21

😲😲 Sounds interesting!

But...

HOW THE F$CK DO YOU IMPLEMENT REACT ON A SERVER?!?!? :O Completely confused...

Orkhan Jafarov • Feb 7 '21

LOL :D
React.js is only a structure, state and etc. It doesn't have any idea what it should render, for example you use React.js with react-dom or react-native, these two libs just rendering what they need depends on react structure.
I'll write an article about how I build this :)

Clifford Fajardo • Feb 13 '21

At high level, your compiler of choice (typescript/babel etc) will take the code and output out code that is valid on the platform your intending to run on.
So those JSX looking tags in react-express examples above will get transformed to regular javascript function calls

This is similar to how JSX tags in react get transformed to plain old javascript function calls after

TLDR: a compiler is converting this code into "valid" code that can later run in the javascript runtime.

medium.com/@sweetpalma/gooact-reac...

Myzel394 • Feb 13 '21

Yeah that makes sense - thank you very much. But how do more complex functions work? E.g useState or useContext

Clifford Fajardo • Feb 13 '21 • Edited

In the example below, just think of useContext as regular javascript function that returns an object, which you are then destructing to get values from for now

export const TopNav = () => {
  const { req, res } = useContext(context);
  return (
    <TopWrapper currentPath={req.originalUrl}>
      <Logo href="/"> </Logo>
      <NavItem href="/">Home</NavItem>
      <NavItem href="/components">Components</NavItem>
      <NavItem href="https://github.com/gigantz/react-xpress">Github</NavItem>
    </TopWrapper>
  );
};

At this stage in the project it seems like this in its initial phases & that useContext is more of a nice expressive and familiar syntax being brought from the react frontend style coding to the backend and isn't doing all complex stuff like re-rendering data and stuff? (i could be wrong
CC @orkhanjafarovr )

On the frontend we use context for lots of things, one being sharing state across the application, when a value in the context changes all components subscribed to that context will update.

That example snippet above reminds of the work that the react team is doing with react server components to some degree

export const TopNav = () => {
  const { req, res } = useContext(context);
  //imagine if "req". was given a new `originalUrl` value from the client via an UPDATE request
  // I could see this creating a new HTML markup tree on the server that could then
  // be streamed to the client & being hot swapped with the older
  // markup in the DOM

  return (
    <TopWrapper currentPath={req.originalUrl}>
      <Logo href="/"> </Logo>
      <NavItem href="/">Home</NavItem>
      <NavItem href="/components">Components</NavItem>
      <NavItem href="https://github.com/gigantz/react-xpress">Github</NavItem>
    </TopWrapper>
  );
};

See this part of the react-server components announcements

youtu.be/TQQPAU21ZUw?t=2064

Again this high level thinking with some background in compilers without seeing source code

@orkhanjafarovr did mention this a bit more about this further down in the comments

dev.to/orkhanjafarovr/comment/1bc16

Myzel394 • Feb 13 '21

Thank you, do you have any articles, videos you can recommend to learn react more in depth?

Orkhan Jafarov • Feb 13 '21

@cliffordfajardo
Thanks for detailed answers! You're awesome, mate ✨

Yep, we can use useContext and it will work as expected, in @reactend/express you can import ReqResContext and pass into useContext to have access req, res

It's also possible to replace appHOC/appWrapper of pages and replace html template.
You can do like this (Sorry for bad naming, I'll change them later to better ones)

registerApp(ExpressApp, {
  appHOC: (Component) => (
    <ReduxProvider store={store}>
      <Component />
    </ReduxProvider>
  ),
  renderHTML: ({ head, styles, root }) => `
    <html>
      <head>
        ${head}
        ${styles}
      </head>
      <body>${root}</body>
    </html>
  `,
});

Clifford Fajardo • Feb 13 '21 • Edited

I like these articles:

Vanilla Hooks outside of react
- this is 1 of those types of articles that helps alot if you code along with it. These links in here are awesome

These Github users below write lots of cool micro libraries for learning purposes, here are tiny react clone in modern JS

A general resource I like to often refer to is this one, when I'm curious about a technology & how it works under the hood

github.com/danistefanovic/build-yo...

Paid resource

KentC Dodds has a react course (epicreact.dev/) covering nearly everything you would need. It's fairly expensive depending on how you view the investment. 5 months ago, I joined a company that uses React. I had production experience with Angular/Vue, vanillaJS and only dabbling with React. I wanted a resource that was cohesive and didn't want to spend time hunting and pieces resources together and building a fragmented view of the react ecosystem so I bought his course. I thought about it like this: Companies pay thousands of dollars for the expertise of someone like Kent C Dodd (author of several top GitHub libraries) and he's offering a course for a few hundred bucks that's replayable and in video with awesome examples..., if I can learn from one of the best that sounds amazing to me
Epic React
Kent's awesome React blog

wchamithu • Feb 8 '21

Waiting for it

Myzel394 • Feb 8 '21

Have you already thought about a name? Maybe something like Rexpress, Exact, Expract.....?

Orkhan Jafarov • Feb 8 '21

Actually the best option is react-express, but it's taken(
But there're options (Rexpress too!) I would like to use to name it, but a bit later :)

Irman itu Aku • Feb 9 '21

Ill waiting for it.

Elliot Wong • Feb 8 '21

Can't wait, would be nice if there's an interactive demo on your heroku site too!

Orkhan Jafarov • Feb 8 '21

For now there's only demo website - react-xpress-demo.herokuapp.com
That built by using the way described above

Chad Adams • Feb 8 '21

So you’re turning React into PHP aye?

Orkhan Jafarov • Feb 11 '21

It’s something like, “build your server with only html skills” lol. Part of the truth, but I’m working on its updates and sandbox. Soon you’ll be able to play with that

Maciek Grzybek • Feb 9 '21

The circle of life :)

neoan • Feb 9 '21

I am not sure if even yourself are aware of how many problems such a solution solves.
I am working on a similar concept (it's VueJS and neoan3 instead of React and express, but the principal is the same). Maybe once you solved your components this will give you some ideas: youtu.be/FBLR28qquCI

Marco Afonso • Feb 11 '21

How better is compared to Next.js?

Orkhan Jafarov • Feb 11 '21

This one is http server that described with jsx. It can render regular react dom components when you pass it to get response (like a template engine does)
I’m working on its package and it will be possible to play with that in sandbox.

Marco Afonso • Feb 11 '21

Oh I see the difference is declaring with JSX... ok.
But at the end will do the same SSR, right?

Orkhan Jafarov • Feb 11 '21

It gonna do only SSR for now, it's more about backend/http-server part than frontend

Marco Afonso • Feb 11 '21

I like JSX... looks nice =)

Renato Ribeiro • Feb 11 '21

not the same purpose

Marco Afonso • Feb 11 '21

Considering rendering React in server side, Nextjs does this. What Am I missing?

Clifford Fajardo • Feb 13 '21 • Edited

This is adding another level of abstraction on top of writing vanilla javascript code to generate a server code; so instead of writing the code that looks the your typical functional that looks like an express handler, you'd write this it seems

react-express -> spits out server infrastructure code

app.get('/', function (req, res) {
  ............other boilerplate code
  res.send('hello world')
})

Side note: I really appreciated the power of declarative languages and built a better mental model on the when/why you would do this after reading Ch2 of Designing Data Intensive Applications by Martin Kleppman

amazon.com/Designing-Data-Intensiv...

A declarative query language can be more attractive because:

it is typically more concise and easier to work with than an imperative API
But more importantly, it also hides implementation details of the underlying code making it possible for the system to introduce performance improvements without requiring any changes to userland code Other examples
- (SQL, you write declarative queries, the engine/query optimizer handles trying to generate the most efficient code for you under the hood given the declarative code)

Andrew Brown 🇨🇦 • Feb 8 '21

Such a good banner image

Burak Saraloglu • Feb 8 '21

They found our secret solution :(
Hide Next.js into shelters

Rohan Salunke • Feb 10 '21

This is cool! ReactPHP might be a more relevant name thought JK :P

Bdw, What rendering engine did you use?

Hammed Oyedele • Feb 11 '21 • Edited

Did you know why you need to use react and react-dom when building React.js projects?

Because React just provides the logic but depends on a renderer to actually output stuff which is where react-dom comes in to render the UI to the browser DOM.

There is a lesser-known package called react-reconciler which is the package react-dom is using and it is what you will use to create your own custom React.js renderers.

Clifford Fajardo • Feb 13 '21

Good callout @devhammed !

Orkhan Jafarov • Feb 11 '21

Yes, that’s exactly as Hammed described. The solution is component based http server and you can pass your regular react dom components and render them. Use useContext hook to get req, res in the components you gonna pass in it