javascript - Toggle Class in React

Question

I'm using react for a project where I have a menu button.

<a ref="btn" href="#" className="btn-menu show-on-small"><i></i></a>

And a Sidenav component like:

<Sidenav ref="menu" />

And I wrote the following code to toggle the menu:

class Header extends React.Component {

    constructor(props){
        super(props);
        this.toggleSidenav = this.toggleSidenav.bind(this);
    }

    render() {
        return (
          <div className="header">
            <i className="border hide-on-small-and-down"></i>
            <div className="container">
          <a ref="btn" href="#" className="btn-menu show-on-small"><i></i></a>
          <Menu className="menu hide-on-small-and-down"/>
          <Sidenav />
        </div>
          </div>
        )
    }

    toggleSidenav() {
        this.refs.btn.classList.toggle('btn-menu-open');
    }

    componentDidMount() {
        this.refs.btn.addEventListener('click', this.toggleSidenav);
    }

    componentWillUnmount() {
        this.refs.btn.removeEventListener('click', this.toggleSidenav);
    }
}

The thing is that this.refs.sidenav is not a DOM element and I cant add a class on him.

Can someone explain me how to toggle class on the Sidenav component like I do on my button?

Answer 1

You have to use the component's State to update component parameters such as Class Name if you want React to render your DOM correctly and efficiently.

UPDATE: I updated the example to toggle the Sidemenu on a button click. This is not necessary, but you can see how it would work. You might need to use "this.state" vs. "this.props" as I have shown. I'm used to working with Redux components.

constructor(props){
    super(props);
}

getInitialState(){
  return {"showHideSidenav":"hidden"};
}

render() {
    return (
        <div className="header">
            <i className="border hide-on-small-and-down"></i>
            <div className="container">
                <a ref="btn" onClick={this.toggleSidenav.bind(this)} href="#" className="btn-menu show-on-small"><i></i></a>
                <Menu className="menu hide-on-small-and-down"/>
                <Sidenav className={this.props.showHideSidenav}/>
            </div>
        </div>
    )
}

toggleSidenav() {
    var css = (this.props.showHideSidenav === "hidden") ? "show" : "hidden";
    this.setState({"showHideSidenav":css});
}

Now, when you toggle the state, the component will update and change the class name of the sidenav component. You can use CSS to show/hide the sidenav using the class names.

.hidden {
   display:none;
}
.show{
   display:block;
}