Module not found @material-ui/core/ThemeProvider when minimizing bundle size in create react app

[NixBiks]

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

I get

Module not found: Can't resolve '@material-ui/core/ThemeProvider'

Expected Behavior 🤔

I don't expect any errors.

Steps to Reproduce 🕹

Since this is a bug related to the project setup then I can't make a codesandbox for it

Steps:

1. npx create-react-app my_app --template typescript
2. install material core 5.0.0-alpha.13
3. npm add -D babel-plugin-transform-imports react-app-rewired customize-cra
4. Update package.json and create .babelrc.js, config-overrides.js files as outlined in the docs.
5. create source content as in this example.

Context 🔦

Your Environment 🌎

Tech	Version
Material-UI	v5.0.0-alpha.13
React	v16.14.0
Browser
TypeScript	v4.0.3
etc.

[NixBiks]

FYI. I've tried both

import { createMuiTheme } from '@material-ui/core/styles';

and

import { createMuiTheme } from '@material-ui/core';

without any luck

[eps1lon]

It doesn't look like this bug report has enough info for one of us to reproduce it.

Please provide a CodeSandbox (https://material-ui.com/r/issue-template), a link to a repository on GitHub, or provide a minimal code example that reproduces the problem.

Here are some tips for providing a minimal example: https://stackoverflow.com/help/mcve

[eps1lon]

Nevermind, I think I know what's happening. We changed the bundle layout and this section is now outdated.

[NixBiks]

Is there a workaround currently? Or should I wait for this issue to be solved?

[eps1lon]

Right now I would not alias @material-ui/core since the improved startup time should be negligible. It only really makes a difference for @material-ui/icons where the documented approach still works.

[NixBiks]

So you are suggesting not using option 2 for now?

[eps1lon]

So you are suggesting not using option 2 for now?

I suggest using option 1 only for @material-ui/icons only where it has the biggest benefit. Anything not using babel plugins should be safe regardless.

[oliviertassinari]

This issue was first reported in https://twitter.com/_developit/status/1220760229790523392. What if we normalize the file structure to make it work without any configuration?