Converting Material UI function to a class

You can convert functional components to class base components.

1. Use normal css.
2. Use import { withStyles } from "@material-ui/core/styles"; for HOC.
3. Use const { classes } = this.props;

Functional Components

import React from "react";
import { makeStyles } from "@material-ui/core/styles";
import ExpansionPanel from "@material-ui/core/ExpansionPanel";
import ExpansionPanelSummary from "@material-ui/core/ExpansionPanelSummary";
import ExpansionPanelDetails from "@material-ui/core/ExpansionPanelDetails";
import Typography from "@material-ui/core/Typography";
import ExpandMoreIcon from "@material-ui/icons/ExpandMore";

const useStyles = makeStyles(theme => ({
    root: {
        marginLeft: 250,
        marginRight: 10
    },
    heading: {
        fontSize: theme.typography.pxToRem(15),
        fontWeight: theme.typography.fontWeightRegular
    }
}));

export default function SimpleExpansionPanel() {
    const classes = useStyles();
    return (
        <div className={classes.root}>
            <ExpansionPanel>
                <ExpansionPanelSummary
                    expandIcon={<ExpandMoreIcon />}
                    aria-controls="panel1a-content"
                    id="panel1a-header">
                    <Typography className={classes.heading}>Expansion Panel 1</Typography>
                </ExpansionPanelSummary>
                <ExpansionPanelDetails>
                    <Typography>
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse
                        malesuada lacus ex, sit amet blandit leo lobortis eget.
                    </Typography>
                </ExpansionPanelDetails>
            </ExpansionPanel>
        </div>
    );
}

Class Base Component

import React from "react";
import ExpansionPanel from "@material-ui/core/ExpansionPanel";
import ExpansionPanelSummary from "@material-ui/core/ExpansionPanelSummary";
import ExpansionPanelDetails from "@material-ui/core/ExpansionPanelDetails";
import Typography from "@material-ui/core/Typography";
import ExpandMoreIcon from "@material-ui/icons/ExpandMore";
**import { withStyles } from "@material-ui/core/styles";**

const useStyles = theme => ({
    root: {
        marginLeft: 250,
        marginRight: 10
    },
    heading: {
        **fontSize: "1rem",**
        fontWeight: theme.typography.fontWeightRegular
    }
});

class SimpleExpansionPanel extends React.Component {
    render() {
        **const { classes } = this.props;**
        return (
            <div className={classes.root}>
                <ExpansionPanel>
                    <ExpansionPanelSummary
                        expandIcon={<ExpandMoreIcon />}
                        aria-controls="panel1a-content"
                        id="panel1a-header">
                        <Typography className={classes.heading}>
                            Expansion Panel 1
                        </Typography>
                    </ExpansionPanelSummary>
                    <ExpansionPanelDetails>
                        <Typography>
                            Lorem ipsum dolor sit amet, consectetur adipiscing elit.
                            Suspendisse malesuada lacus ex, sit amet blandit leo lobortis
                            eget.
                        </Typography>
                    </ExpansionPanelDetails>
                </ExpansionPanel>
            </div>
        );
    }
}

**export default withStyles(useStyles)(SimpleExpansionPanel);**

Just add that into the render, like so (change it to this.props):

  render() {
    const { classes } = this.props;
    return (