Converting Material UI function to a class

Question

How do I convert a React function to a class? I don't understand how to update const { classes } = props; in a function to class use. Here is a button function from Material UI: https://material-ui-next.com/demos/buttons/

import React from 'react';
import PropTypes from 'prop-types';
import { withStyles } from 'material-ui/styles';
import Button from 'material-ui/Button';

const styles = theme => ({
  button: {
    margin: theme.spacing.unit,
  },
  input: {
    display: 'none',
  },
});

function RaisedButtons(props) {
  const { classes } = props;
  return (
    <div>
      <Button variant="raised" className={classes.button}>
        Default
      </Button>
      <Button variant="raised" color="primary" className={classes.button}>
        Primary
      </Button>
      <Button variant="raised" color="secondary" className={classes.button}>
        Secondary
      </Button>
      <Button variant="raised" color="secondary" disabled className={classes.button}>
        Disabled
      </Button>
      <input
        accept="image/*"
        className={classes.input}
        id="raised-button-file"
        multiple
        type="file"
      />
      <label htmlFor="raised-button-file">
        <Button variant="raised" component="span" className={classes.button}>
          Upload
        </Button>
      </label>
    </div>
  );
}

RaisedButtons.propTypes = {
  classes: PropTypes.object.isRequired,
};

export default withStyles(styles)(RaisedButtons);

Here is my conversion to a React class component. It currently gives me an error message of 'classes' is not defined no-undef since I am missing the classes = props part.

import React, { Component } from 'react';
import Button from 'material-ui/Button';
import MuiThemeProvider from 'material-ui/styles/MuiThemeProvider';
import MyTheme from './MyTheme';
import './App.css';
import { withStyles } from 'material-ui/styles';
import PropTypes from 'prop-types';


const styles = theme => ({
  button: {
    margin: theme.spacing.unit,
  },
  input: {
    display: 'none',
  },
});


class App extends Component {
  constructor(props)
  {
    super(props);
  }  

  render() {
    return (
      <MuiThemeProvider theme={MyTheme}>
          <Button variant="raised" >
          Default
          </Button>
          <Button variant="raised" color="primary" className={classes.button}>
          Primary
          </Button>
          <Button variant="raised" color="secondary" className={classes.button} >
          Secondary
          </Button>
          <Button variant="raised" color="secondary" className={classes.button}>
          Disabled
          </Button>
          <input
              accept="image/*"
              className={classes.input}
              id="raised-button-file"
              multiple
              type="file"
          />
          <label htmlFor="raised-button-file">
          <Button variant="raised" component="span" >
            Upload
          </Button>
          </label>
      </MuiThemeProvider>
      );
  }
}

App.propTypes = {
  classes: PropTypes.object.isRequired,
};

export default withStyles(styles)(App);

Answer 1

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

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

Answer 2

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);**