import React, { PureComponent } from 'react'; import './Sidebar.css'; export class Sidebar extends PureComponent { constructor(props) { super(props); // this.sidebar_ref = React.createRef(); this.do_close_bound = this.do_close.bind(this); this.do_back_bound = this.do_back.bind(this); } do_close() { this.props.show_sidebar(null, null, 'clear'); } do_back() { this.props.show_sidebar(null, null, 'pop'); } render() { // hide old contents to remember state let contents = this.props.stack.map( ({ 1: content }, i) => content && (