[material-ui][Typography] Enforce responsive typography type checking in `sx` prop

[goodwin64]

Summary

Here the typography shorthand has a string type as it's later being spread into the element.

We use responsive typography as in the following example:

<Typography
  sx={{
    typography: {
      xs: 'Body S',
      sm: 'Body M',
      md: 'any string is valid here',
    },
  }}
>
  The size of this text changes based on the screen size. Check it out! <br />
  In most cases, we will reuse the same typography variant across breakpoints. But
  in case you need to override it, refer to the code in this example.
</Typography>

and there's no way for TypeScript to catch the types inconsistency early in the process.

I tried a bunch of things to redeclare typography prop but with no luck. E.g.:

// attempt 1
declare module '@mui/system' {
  interface SxProps<Theme = MUITheme> extends MUISxProps<Theme> {
    typography?: {
      [key in Breakpoint]?: FlashPackTypographyVariant;
    } | FlashPackTypographyVariant;
  }
}

// attempt 2
declare module '@mui/system' {
  interface TypographyPropsVariantOverrides {
    // Your custom typography variants (as before)
  }

  interface AliasesCSSProperties {
    // Add your custom property here
    typography?: {
      [key in Breakpoint]?: FlashPackTypographyVariant;
    } | FlashPackTypographyVariant;
  }

  // This ensures the custom property is recognized in the theme
  interface ThemeOptions {
    typography?: TypographyOptions | ((theme: Theme) => TypographyOptions);
  }
}

// attempt 3
declare module '@mui/material/styles' {
  interface CSSProperties {
    typography?: {
      [key in Breakpoint]?: FlashPackTypographyVariant;
    } | FlashPackTypographyVariant;
  }
}

I'd love to get some tips if there's a way to override typography in this case!

Examples

No response

Motivation

No response

Search keywords: typography, typescript, override, generic

[ZeeshanTamboli]

Instead of allowing type overrides in the sx prop's typography property, we should enforce type checking. For the Typography component, we can make the following changes:

--- a/packages/mui-material/src/Typography/Typography.d.ts
+++ b/packages/mui-material/src/Typography/Typography.d.ts
@@ -1,6 +1,6 @@
 import * as React from 'react';
 import { OverridableStringUnion } from '@mui/types';
-import { SxProps, SystemProps } from '@mui/system';
+import { SxProps, SystemProps, Breakpoint } from '@mui/system';
 import { Theme } from '../styles';
 import { OverrideProps, OverridableComponent } from '../OverridableComponent';
 import { Variant } from '../styles/createTypography';
@@ -43,7 +43,9 @@ export interface TypographyOwnProps extends SystemProps<Theme> {
   /**
    * The system prop that allows defining system overrides as well as additional CSS styles.
    */
-  sx?: SxProps<Theme>;
+  sx?: SxProps<Theme> & {
+    typography?: string | Partial<Record<Breakpoint, TypographyProps['variant']>>;
+  };
   /**
    * Applies the theme typography styles.
    * @default 'body1'

We cannot implement this in AliasesCSSProperties because the Variant type from Material UI is not available in the MUI System. While we may need this change for all sx types across all Material UI components, applying it to the Typography component is a good start.

In-case anybody is creating a new PR, make sure to add a TypeScript test case.

[Sergio16T]

Hello @ZeeshanTamboli! I'm beginning to work on a fix for this issue. Could you please assign it to me?

[ZeeshanTamboli]

@Sergio16T Assigned!

[Sergio16T]

Hello @ZeeshanTamboli! I opened a PR with fix. Ready for review

[rkumar261]

Is this issue already resolved? If not, I'm interested in working on it.

[Sergio16T]

Hi @rkumar261 the dev work is complete. PR is awaiting final review from maintainers.

[rkumar261]

Ok @Sergio16T, thanks