Accessing previous theme variables in createMuiTheme
You'd need to create an instance of the default theme and use it when defining your own:
import { createMuiTheme } from 'material-ui/styles';const defaultTheme = createMuiTheme();const theme = createMuiTheme({ typography: { fontSize: defaultTheme.typography.fontSize + 2 }});export default theme;
You can also create your theme and then add on to it after theme is created.
import { createMuiTheme } from 'material-ui/styles';const theme = createMuiTheme();theme.typography = { ...theme.typography, fontSize: theme.typography.fontSize + 2}export default theme;