Multiple themes with TypeScript merge declaration does not work properly

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Steps to reproduce 🕹

Link to live example:

Steps:

1. Use Nx and generate one of several libraries
2. Create multiple themes and use TypeScript merge declaration to get intellisense (as per the docs)
3. As soon as you export multiple themes in your Nx monorepo, they will clash and TS will read all of them, meaning that for example if theme X has a "myVariant1" custom typography variant and theme Y has another, TS will read them all and want you to fill all of them out, in all of the themes.

Current behavior 😯

TypeScript is reading all of the merge declarations for all of your themes as soon as you export more than one theme.

Expected behavior 🤔

Types should be isolated to their theme and not exposed to the whole monorepo. Not sure how you'd solve this, but ideally you could look to other TypeScript solutions than merge declarations. Chakra UI does it by installing files into node_modules for example.

Context 🔦

We have a monorepo with many apps and many themes. We want full TypeScript support for all of them, but currently that's not really feasible if you use Nx at least.

Your environment 🌎

  System:
    OS: Linux 5.15 Ubuntu 22.04.1 LTS 22.04.1 LTS (Jammy Jellyfish)
  Binaries:
    Node: 18.13.0 - ~/.nvm/versions/node/v18.13.0/bin/node
    Yarn: 3.2.3 - ~/.nvm/versions/node/v18.13.0/bin/yarn
    npm: 8.19.3 - ~/.nvm/versions/node/v18.13.0/bin/npm
  Browsers:
    Chrome: Not Found
    Firefox: Not Found
  npmPackages:
    @emotion/react: ^11.7.1 => 11.7.1 
    @emotion/styled: ^11.6.0 => 11.6.0 
    @mui/base:  5.0.0-alpha.65 
    @mui/icons-material: ^5.4.4 => 5.4.4 
    @mui/material: ^5.3.0 => 5.3.0 
    @mui/private-theming:  5.3.0 
    @mui/styled-engine:  5.3.0 
    @mui/system:  5.3.0 
    @mui/types:  7.1.0 
    @mui/utils: ^5.3.0 => 5.3.0 
    @types/react: 18.0.1 => 18.0.1 
    react: ^18.1.0 => 18.1.0 
    react-dom: ^18.1.0 => 18.1.0 
    typescript: ^4.9.5 => 4.9.5