Toggle div-elements in different component in React

Question

I'm fairly new to React. I'm trying to build a site where you can click navigation item (in this case music genre) and it will list all the songs that belongs to that particular genre.

My app.js looks like this:

import React, { Component } from 'react';
import ListGenres  from './ListGenres';
import './App.css';


class App extends Component {
    constructor(props) {
      super();
      this.state = {dataList: props.dataList};
    }
    render() {
      return (
        <div>
          <div className="App">
            <Navigation tracks = {this.state.dataList} />
            <ListGenres tracks = {this.state.dataList}/>
          </div>
        </div>
     );
   }
}

export default App;

I have a navigation component that looks like this:

import React from 'react';
import HeaderBar  from './HeaderBar'; 
import MenuItem from 'material-ui/MenuItem';

export class Navigation extends React.Component {
constructor(props) {
    super();
}
/*
onClickFunction() {
    toggle elements in another component
}
*/
render() {
    const genres = this.props.tracks.map((elem) => {
        return elem.genre;
    });
    const filtered = genres.filter((elem, index, self) => {
      return self.indexOf(elem) === index;
    });
    const genreLoop = filtered.map((elem, i) => {
      return (
        <MenuItem 
            onClick= {this.onClickFunction}
            key={ i }><a>{ elem }</a>
        </MenuItem>);
    });
    return (
        <div>
            { genreLoop }
        </div>
    );
  }
}
export default Navigation;

My list of items are rendered in another component whick looks like this:

import React from 'react';
import './ListGenres.css';

export class ListGenres extends React.Component {
    constructor(props) {
    super();
}
render() {
    return (
        <div className="genreList">
            <div className="tracklist-visible tracklist-pop">
                <ul>
                    <h3>Pop</h3>
                    { this.tracklist('Pop') }   
                </ul>
            </div>
            <div className="tracklist-visible tracklist-metal">
                <ul>
                    <h3>Pop</h3>
                    { this.tracklist('Metal') } 
                </ul>
            </div>
        </div>
   );
}

Is there way to maybe add css-class to tracklist-div when anchor is clicked from Navigation-component? Looks like I can't pass any props from that component since it's "stand-alone"-component?

Answer 1

You didn't supply much code or example on how things should work but as i understand you are looking for a behavior similar to Tabs, where you click a Tab and a corresponding View is presented.
If this is the case, then you need a Parent component that will manage the selected Tabs and render the View respectively. This is a simple example:

const tabs = ["Pop", "Rock", "Rap", "Electro"];

const View = ({name}) => <h1 className="view">{`This is ${name} music!`}</h1>

class Tab extends React.Component {
  constructor(props) {
    super(props);

    this.onClick = this.onClick.bind(this);
  }

  onClick() {
    const { id, onClick } = this.props;
    onClick(id);
  }

  render() {
    const { name, id, isSelected } = this.props;
    const css = `tab ${isSelected && 'selected'}`;
    return (
      <div
        className={css}
        onClick={this.onClick}
      >
      {name}
      </div>
    );
  }
}

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      selectedTab: 1
    }

    this.onTabChange = this.onTabChange.bind(this);
  }

  onTabChange(id) {
    this.setState({ selectedTab: id });
  }

  render() {
    const { selectedTab } = this.state;
    return (
      <div>
        {
          tabs.map((t, i) => {
              return (
              <div className="wrapper">
                <Tab name={t} id={i + 1} isSelected={selectedTab === i + 1} onClick={this.onTabChange} />
                {selectedTab == i + 1 && <View name={t} />}
              </div>
              )
            })
        }
      </div>
    );
  }
}

ReactDOM.render(<App />, document.getElementById('root'));

.tab {
  display: inline-block;
  margin: 0 10px;
  width: 60px;
  text-align: center;
  cursor: pointer;
  padding: 5px;
}

.selected {
  border: 1px solid #eee;
  box-shadow: 0 0 3px 1px #999;
}

.wrapper{
  display:inline-block;
}

.view{
  position: absolute;
  top: 0;
  left: 0;
  margin-top: 50px;
  text-align: center;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"></div>

Answer 2

You need to lift the state up.

Of course, you can solve this with Redux too, but let's keep it simple and only use React.

Lifting State Up

Create a component that will contains both <Navigation /> and <ListGenres /> components.

Keep the state (genre and selectedGenre) in this parent component and pass it down through props.

You also need to create a callback to handle genres changes.

Here's the example:

class App extends Component {
  constructor (props) {
    super(props)
    this.state = {
      selectedGenre: null,
      genres: [...]
    }
  }

  onGenreChange (genre) {
    this.setState({ selectedGenre: genre })
  }

  render () {
    return (
      <div>
        <Navigation
          onGenreChange={genre => this.onGenreChange(genre)}
          genres={this.state.genres}
        />
        <ListGenres
          genres={this.state.genres}
          selectedGenre={this.state.genres}
        />
      </div>
    )
  }
}