Can this be used in a single spa application?

[kennyist]

I'm having issues using tss-react in a single spa environment. In my root app, I am able to get the UMD version of MUI and emotion (not been able to find an umd/systemjs version of this package or create one successfully):

        "@mui/material": "https://unpkg.com/@mui/material@5.4.3/umd/material-ui.production.min.js",
        "@emotion/react": "https://cdn.jsdelivr.net/npm/@emotion/react@11.8.2/dist/emotion-react.umd.min.js",
        "@emotion/styled": "https://cdn.jsdelivr.net/npm/@emotion/styled@11.8.1/dist/emotion-styled.umd.min.js",

And they are being externalised by webpack in the sub app I am trying to use tss-react, In this app I have created a cache as the docs showed:

export const muiCache = createCache({
    'key': 'mui',
    'prepend': true,
  });

// region Component

const Theme: FunctionComponent<IThemeProps> = ({
  children,

  style
}) => {
  // handlers

  const theme = React.useMemo(() => {
    switch (style) {
      case Themes.Default:
      default:
        return DefaultTheme;
    }
  }, [style]);

  // render

  return (
    <CacheProvider value={muiCache}>
      <MuiThemeProvider theme={theme}>
        {children}
      </MuiThemeProvider>
    </CacheProvider>
  );
};

But MUI css always takes precedence over tss-react created styles and cannot seem to get it to work. Is there a way to get this to work?

[garronej]

Hello @kennyist,
Is the code of your your repo open source?

[garronej]

There is this example of tss-react setup on a SPA: https://github.com/garronej/tss-react/tree/main/src/test/apps/spa

you can run it with:

git clone https://github.com/garronej/tss-react
cd tss-react
yarn
yarn build
yarn start_spa

Regarding why it's not working in your case, I can't know with the fiew informations you provided me.
I think you have multiple copy of @emotion/react in your dependency and MUI is not picking up your cache. You chan change the key by something random and go see in the debug devloper console if you see it appear.
I will will gladly debug your depo if you provide me the code or a sandbox.

[kennyist]

Hi @garronej, thanks for the reply. Unfortunately cannot give access to the main repo, But I have made a quick setup in the same style being used at the moment, with it also not working there. This is using single spa for microservice setup.

[garronej]

Thank you for setting up this sample repo.
Unfortunately I can't get it to run.
I did:

git clone https://github.com/kennyist/tss-react-test
cd tss-react-rest
cd ui
npm install
npm run npm run start:standalone

I am getting this:

Please provide additional informations to help me reproduce the specifical issue you are facing related to tss-react

[kennyist]

Ah sorry, You need to clone the repo and then do this for each sub folder (ui, root, page)

cd tss-react-test
cd <SUB FOLDER>
npm install
npm start

Once all are running at the same time, go to http://localhost:9000. You should then get a MUI button, This has a className style to change the background to red that 'MUI' overrides.

[garronej]

Hi @kennyist,
So, I spend an hour trying to sort this out I understand what the problem is but unfortunately I am not familiar enough with single-spa to provide a working setup.
The problem is not related to TSS react, @emotion/react is supposed to be a dependency shared by @mui/material and tss-react. Like react or react-dom are shared across the App.
In your setup @mui/material internally uses an other instance of @emotion/react that you are when you import { CacheProvider } from "@emotion/react".
As a result, when you provide you cache with<CacheProvider> it is never picked up by @mui/material.

This is a problem not only for TSS but also potentially for other libraries you might be using.
I'd suggest submitting an issue to single-spa and/or emotion.

Please let me know it you manage to sort it out.
Best

[garronej]

Hi @kennyist. Have you find a solution to this?
When this is is done I think the problem will solve itself but still, I would like to figure out why @emotion/react can't be shared even tho you seems to have setup single-spa well...

[liztownd]

Hi @kennyist - just wanted to check to see if you've had any success with this issue? I'm running into the same thing with my single-spa app (set up very similarly to your test repo you linked above) and cannot make the tss-styles override the MUI generated css-styles (have tried <StyledEngineProvider injectFirst> as well as the recommended <CacheProvider> set up). Have you had any luck figuring out a workaround? Thanks!

[garronej]

Hi @liztownd,
I am sorry I didn't get the chance to try again.
There is still this MUI PR going on that should fix this issue.
For now all I can tell is that this is the root cause:

The problem is not related to TSS react, @emotion/react is supposed to be a dependency shared by @mui/material and > tss-react. Like react or react-dom are shared across the App.
In your setup @mui/material internally uses an other instance of @emotion/react that you are when you
import { CacheProvider } from "@emotion/react".
As a result, when you provide you cache with it is never picked up by @mui/material.

If you manage to setup single-spa in such a way that @emotion/react is not duplicated in your code, you win.

[liztownd]

@garronej & @kennyist -- I WIN! Lol.

In the root-config file when registering the sub applications I passed an instance of the createCache & CacheProvider from @emotion, then picked them up from the props rather than importing them in each sub-app (I had several apps all importing their own theme object and assigning classNames). Voila, I now have one muiCache, and the styles are appearing in order, pre-prending the tss styles, each with their own prefix depending on the sub-app they originated from.

in root-config:

import { registerApplication, start } from "single-spa";
import {
  constructApplications,
  constructRoutes,
  constructLayoutEngine,
} from "single-spa-layout";
import microfrontendLayout from "./microfrontend-layout.html";
import { CacheProvider } from "@emotion/react";
import createCache from "@emotion/cache";

const routes = constructRoutes(microfrontendLayout);
const applications = constructApplications({
  routes,
  loadApp({ name }) {
    return System.import(name);
  },
});
const layoutEngine = constructLayoutEngine({ routes, applications });

const applicationsWithProps = applications.map((application) => {
  return {
    ...application,
    customProps: { createCache: createCache, CacheProvider: CacheProvider },
  };
});

applicationsWithProps.forEach(registerApplication);

layoutEngine.activate();
start();

inside cache provider in every sub app:

import { ReactChild } from "react";
import type { CacheProvider } from "@emotion/react";
import type createCache from "@emotion/cache";

export type Props = {
  CacheProvider: typeof CacheProvider;
  createCache: typeof createCache;
  children?: ReactChild;
};

export function Theme(props: Props) {

  const { CacheProvider, createCache, children } = props;

  const muiCache = createCache({
    "key": "mui", // to test in each sub app I assigned a different "key", they should all show up in one cache
    "prepend": false
  });

  return <CacheProvider value={muiCache}>{children}</CacheProvider>;

};

[garronej]

@liztownd awesome, nicely done!
Thank you very much for your contribution.
I will add a section in the documentation website.

[tristan-cunningham]

@liztownd
@garronej Documentation may need to change if you have made it

Your solution causes single spa inspector dev tool to not work, infinite loading. This seems like it will happen if you use single spa layout engine.

To fix this, don't create a new array with custom props added (applicationsWithProps in your example). Add the props to the route constructor like so:

const routes = constructRoutes(microfrontendLayout, {
  props: {
    createCache: createCache,
    CacheProvider: CacheProvider
  },
  loaders: {
  }
});

And then in your layout html file add the props to the application like this:

<application name="@your-app" props="createCache,CacheProvider"></application>

[liztownd]

@kennyist nice catch! Thank you! I'm new to single-spa (haven't even installed the single spa inspector dev tools yet) so this is super helpful!