React - how to pass state to another component

Question

I'm trying to figure out how to notify another component about a state change. Let's say I have 3 components - App.jsx,Header.jsx,and SidebarPush.jsx and all I'm simply trying to do is toggle a class with an onClick.

So the Header.jsx file will have 2 buttons when clicked will toggle the states to true or false. The other 2 components App.jsx and Header.jsx will need to know about these state changes so they can toggle a class whenever those states change.

App.jsx

import React from 'react';
import Header from 'Header';
import classNames from "classnames";
import SidebarPush from 'SidebarPush';
import PageWrapper from 'PageWrapper';

var MainWrapper = React.createClass({
    render: function() {
        return (
            <div className={classNames({ 'wrapper': false, 'SidebarPush-collapsed': !this.state.sidbarPushCollapsed })}>
                <Header/>
                <SidebarPush/>
                <PageWrapper>
                {this.props.children}
                </PageWrapper>
            </div>
        );
    }
});

module.exports = MainWrapper;

Header.jsx

import React from 'react';
import ReactDom from 'react-dom';


class Header extends React.Component {
    constructor() {
        super();
        this.state = {
            sidbarPushCollapsed: false,
            profileCollapsed: false
        };
        this.handleClick = this.handleClick.bind(this);
    }
    handleClick() {
        this.setState({
            sidbarPushCollapsed: !this.state.sidbarPushCollapsed,
            profileCollapsed: !this.state.profileCollapsed

        });
    }
    render() {
        return (
            <header id="header">
                <ul>
                    <li>
                        <button type="button" id="sidbarPush" onClick={this.handleClick} profile={this.state.profileCollapsed}>
                            <i className="fa fa-bars"></i>
                        </button>
                    </li>
                    <li>
                        <button type="button" id="profile" onClick={this.handleClick}>
                            <i className="icon-user"></i>
                        </button>
                    </li>
                </ul>
                <ul>
                    <li>
                        <button id="sidbarOverlay" onClick={this.handleClick}>
                            <i className="fa fa-indent"></i>
                        </button>
                    </li>
                </ul>
            </header>
        );
    }
};

module.exports = Header;

SidebarPush.jsx

import React from 'react';
import ReactDom from 'react-dom';
import classNames from "classnames";


class SidebarPush extends React.Component {
    render() {
        return (
            <aside className="sidebarPush">
                <div className={classNames({ 'sidebar-profile': true, 'hidden': !this.state.pagesCollapsed })}>
                        ....
                </div>

                <nav className="sidebarNav">
                        ....
                </nav>
            </aside>
        );
    }
}


export default SidebarPush;

Answer 1

Move all of your state and your handleClick function from Header to your MainWrapper component.

Then pass values as props to all components that need to share this functionality.

class MainWrapper extends React.Component {
    constructor() {
        super();
        this.state = {
            sidbarPushCollapsed: false,
            profileCollapsed: false
        };
        this.handleClick = this.handleClick.bind(this);
    }
    handleClick() {
        this.setState({
            sidbarPushCollapsed: !this.state.sidbarPushCollapsed,
            profileCollapsed: !this.state.profileCollapsed

        });
    }
    render() {
        return (
           //...
           <Header 
               handleClick={this.handleClick} 
               sidbarPushCollapsed={this.state.sidbarPushCollapsed}
               profileCollapsed={this.state.profileCollapsed} />
        );

Then in your Header's render() method, you'd use this.props:

<button type="button" id="sidbarPush" onClick={this.props.handleClick} profile={this.props.profileCollapsed}>