React JS one way data flow confusion

Question!

This is the jquery solution that i want to implement using reactJS

var offCanvass = function() {
        $('body').on('click', '.js-fh5co-nav-toggle', function(event) {

            var $this = $(this);

            $('#fh5co-offcanvass').toggleClass('fh5co-awake');
            $('#fh5co-page, #fh5co-menu').toggleClass('fh5co-sleep');

            if ($('#fh5co-offcanvass').hasClass('fh5co-awake')) {
                $this.addClass('active');
            } else {
                $this.removeClass('active');
            }
            event.preventDefault();

        });
    };

What I am able to do is : By using states and classnames i can change the CSS classes of a particular component on an event inside that component.

var classNames = require('classnames');
export default class App extends React.Component {

    render() {
      var navClass = classNames({
        'js-fh5co-nav-toggle': true,
        'fh5co-nav-toggle': true,

      });
        return (
            <div>
                <Offcanvas/>
                <Menu navClass={navClass}/>
                <Page/>
            </div>
        );
    }
}

export default class Menu extends React.Component {
  constructor(){
    super();
    this.state={
      isPressed: false,
    };
  }

  isPressed(){
    if(!this.state.isPressed){
        this.setState({isPressed: true});
    }else{
       this.setState({isPressed: false});
         }
  }

    render() {
        var navClass = classNames(this.props.navClass, {
          active: this.state.isPressed
        });
        return (
            <div id="fh5co-menu" class="navbar">
              <div class="container">
                <div class="row">
                  <div class="col-md-12">
                    <a class={navClass}  data-toggle="collapse" onClick={this.isPressed.bind(this)} data-target="#fh5co-navbar" aria-expanded="false" aria-controls="navbar"><span></span> <i></i></a>
                    <a href="/index" class="navbar-brand"><span>dota groove<a class=""></a></span></a>
                  </div>
                </div>
              </div>
            </div>
        );
    }
}

export default class Canvas extends React.Component {


  render(){
    return(
        <div id="fh5co-offcanvass">
          <ul>
            <li class="active"><a href="" data-nav-section="home">Home</a></li>
            <li><a href="" data-nav-section="login">Register</a></li>
            <li><a href="" data-nav-section="clients">Login</a></li>
          </ul>
        </div>
    );
  }
}

What I want to do : Use an event from one component to trigger the classname change of another component which are not in top down hierarchy. This is my component structure.

-app
  -canvas ->classname apends here
  -menu ->if click event occurs here
  -page
By : eersteam


Answers

Would the following pattern work for you?

A child component (menu) changes the state of its parent (app) via a click event. Then the parent sends the updated state to its another child (canvas) via a prop.

Here is a a short codecademy exercise that describes this pattern: https://www.codecademy.com/en/courses/react-102/lessons/child-updates-sibling/exercises/child-updates-sibling-intro



Your <App/> needs to handle the event. You can pass a callback function as a prop to <Menu />, on a click this function is called in App. Now the App can react to the click and pass a prop to <Canvas/>.

class App extends Component {
  constructor() {
    super();
    this.state = {clicked: false};
  }

  handleClick() {
    this.setState({clicked: !this.state.clicked});
  }

  render() {
    return (
     <div>
       <OffCanvas isClicked={this.state.clicked} />
       <Menu onClick={() => this.handleClick()} />
     </div>
    );
  }
}

This is a pretty common pattern in react.

Sidenote regarding your jquery example: All you are doing in there can easily be done with "vanilla" JS, no need for jquery.

By : Scarysize


This video can help you solving your question :)
By: admin