[LoadingButton] defaultProps is no longer inherited from MuiButton defaultProps in @mui/lab 5.0.0-alpha.55 version

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Current behavior 😯

I had a theme with changed variant default prop value for MuiButton. The previous versions of @mui/lab applied this value for MuiLoadingButton components. Starting with version 5.0.0-alpha.55 it doesn’t work. Now we need also change default prop value for MuiLoadingButton separately.

Expected behavior 🤔

It should inherit default prop value from MuiButton as MuiLoadingButton component is based on Button and inherits all its props.

Steps to reproduce 🕹

createTheme

const theme = createTheme({
    components: {
        MuiButton: {
            defaultProps: {
                variant: 'contained',
            },
        },
        // MuiLoadingButton: {
        //     defaultProps: {
        //         variant: 'contained',
        //     },
        // },
    }
});

test component

<ThemeProvider theme={theme}>
    <LoadingButton>It should be contained</LoadingButton>
</ThemeProvider>

Context 🔦

No response

Your environment 🌎

`npx @mui/envinfo`

  System:
    OS: macOS 11.6.1
  Binaries:
    Node: 16.8.0 - /usr/local/bin/node
    Yarn: 1.22.11 - /usr/local/bin/yarn
    npm: 7.21.0 - /usr/local/bin/npm
  Browsers:
    Chrome: 95.0.4638.69
    Edge: Not Found
    Firefox: 92.0
    Safari: 15.1
  npmPackages:
    @emotion/react: ^11.5.0 => 11.6.0 
    @emotion/styled: ^11.3.0 => 11.6.0 
    @mui/base:  5.0.0-alpha.55 
    @mui/icons-material: ^5.0.4 => 5.1.1 
    @mui/lab: ^5.0.0-alpha.55 => 5.0.0-alpha.55 
    @mui/material: ^5.1.0 => 5.1.1 
    @mui/private-theming:  5.1.1 
    @mui/styled-engine:  5.1.1 
    @mui/system:  5.1.1 
    @mui/types:  7.1.0 
    @mui/utils:  5.1.1 
    @types/react: ^17.0.0 => 17.0.35 
    react: ^17.0.2 => 17.0.2 
    react-dom: ^17.0.2 => 17.0.2 
    typescript: ^4.4.3 => 4.4.4 

[danderson00]

Not sure why this is closed. Attempting to set MuiButton variant property using defaultProps does not seem to work, as of 5.8.7. Can we reopen, or should I open another issue?

[ZeeshanTamboli]

Sorry to necro this closed issue, but given this change, how does one change the default props for a LoadingButton or other lab components?

I use this approach https://mui.com/material-ui/customization/theme-components/ for @mui/material components,

but if I add a @mui/lab component to the components object, I get a compiler error:

import type { ButtonProps, ThemeOptions } from '@mui/material'
import { createTheme } from '@mui/material'

const btnCommon: Partial<ButtonProps> = {
  variant: 'contained',
}

const themeOptions: ThemeOptions = {
  components: {
    MuiButton: {
      defaultProps: btnCommon,
    },
// TS error:
// Object literal may only specify known properties, and 'MuiLoadingButton' does not exist in type 'Components<BaseTheme>'.
    MuiLoadingButton: {  
      defaultProps: btnCommon,
    },
// ... other components
}

export const MuiOverrides = createTheme(themeOptions)

I tried using any type to allow me to pass MuiLoadingButton in that object, but it has no effect.

If you are using TypeScript, you need to import types by leveraging module augmentation. See: https://mui.com/material-ui/about-the-lab/#typescript