Render elements dynamically using map Reactjs

Here I’m using a component that needs to render multiple ExpansionPanel Material UI components based on data fetched in an array. The map is using Arrow function with () for an implicit return.

Below is the sample code for the Component:

import React, { Component } from "react";
import Header from "./Header";
import { withStyles } from '@material-ui/core/styles';
import ExpansionPanel from '@material-ui/core/ExpansionPanel';
import ExpansionPanelDetails from '@material-ui/core/ExpansionPanelDetails';
import ExpansionPanelSummary from '@material-ui/core/ExpansionPanelSummary';
import Typography from '@material-ui/core/Typography';
import ExpandMoreIcon from '@material-ui/icons/ExpandMore';
import loadingImg from "../images/LoadingImg_EZ.gif";

const styles = (theme) => ({
  root: {
    width: '100%',
  heading: {
    fontSize: theme.typography.pxToRem(15),
    flexBasis: '33.33%',
    flexShrink: 0,
    fontWeight: 'bold',
  secondaryHeading: {
    fontSize: theme.typography.pxToRem(15),
    color: theme.palette.text.secondary,
  OfflineText: {
    fontSize: "20px",
    color: "red",

class MyComponent extends Component {
  constructor(props) {
    this.state = {
      expanded: false,
      panelTypes: null,
      summary: null

  componentWillMount() {
    //get data here and set state.

  handleChange = (panel) => (event, isExpanded) => {
    this.setState({ expanded: isExpanded? panel: false});

  render() {
      const { classes } = this.props;
        <Header />
        {this.state.panelTypes !=null ? (
          <h3 style={{fontSize: "15px", paddingLeft: "4px"}}>Summary</h3>
          <div className={classes.root}>
            { => (
              <ExpansionPanel expanded={this.state.expanded === item.types} onChange={this.handleChange(item.types)}>
                  expandIcon={<ExpandMoreIcon />}
                  style={{backgroundColor: "#e6e6e6"}}
                  <Typography className={classes.heading}>{this.state.panelTypes !=null ? `${item.types} (Year ${item.year})`:''}</Typography>
                    Nulla facilisi. Phasellus sollicitudin nulla et quam mattis feugiat. Aliquam eget
                    maximus est, id dignissim quam.
          </>) : (
          <div id="loading">
            <img id="loading-image" src={loadingImg} alt="Loading..." />


export default withStyles(styles, { withTheme: true })((MyComponent));
panelTypes will hold the array of items that will be used to create the same number of Expansion Panels using in the render method.

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