React.js - How to implement a function in a child component to unmount another child from the same parent, and mount another component on it's place?

Question

For example, a component like this:

import React, { Component } from 'react';
import BodyContent from './BodyContent';
import BottomOne from './BottomOne';
import BottomTwo from './BottomTwo';
class App extends Component {
  render() {
    return (
      <div className="App">
        <BodyContent />
        <BottomOne />
      </div>
    );
  }
}

export default App;

I want to implement a function on BodyContent that unmount BottomOne and mounts BottomTwo instead, so when I activate the function, the code is reestructured to this:

import React, { Component } from 'react';
import BodyContent from './BodyContent';
import BottomOne from './BottomOne';
import BottomTwo from './BottomTwo';
class App extends Component {
  render() {
    return (
      <div className="App">
        <BodyContent />
        <BottomTwo />
      </div>
    );
  }
}

export default App;

I'm very new to React, so if there's a better way to do it, I'm open to suggestions, but I really need that end result, a function on BodyContent that unmounts BottomOne and mounts BottomTwo.

Answer 1

To achieve that maintain a state variable in parent component (some kind of identifier for component) and use that state variable to render different component.

Along with that you also need to pass a function from parent to child and use that function to update the parent state value.

Like this:

class App extends Component {
  constructor(){
    super();
    this.state={
      renderOne: true,
    }
    this.update = this.update.bind(this);
  }

  update(){
      this.setState({renderOne: false})
  }

  render() {
    return (
      <div className="App">
        <BodyContent update={this.update}/>
        {this.state.renderOne?  <BottomOne />  : <BottomTwo/> }
      </div>
    );
  }
}

Now inside BodyContent component call this.props.update() to render another component.

Answer 2

You can use state or props to render different components.

Example:

import React, {
    Component
}
from 'react';
import BodyContent from './BodyContent';
import BottomOne from './BottomOne';
import BottomTwo from './BottomTwo';
class App extends Component {
    constructor(props) {
        super(props);
        this.state = {
            decider: false
        };
    }
    render() {
        const bottomContent = this.state.decider === true ? <BottomOne /> : <BottomTwo />;
        return (
            <div className="App">
                <BodyContent />
                { bottomContent }
            </div>
        );
    }
}
export
default App;

Answer 3

You can maintain a state which tells which component to render. Something roughly like this

import React, { Component } from 'react';
import BodyContent from './BodyContent';
import BottomOne from './BottomOne';
import BottomTwo from './BottomTwo';
class App extends Component {
  changeBottomComponent = (comp) => {
    this.setState({ showBottom: comp})
  }
  render() {
    return (
      <div className="App">
        <BodyContent changeBottomComponent={this.changeBottomComponent}/>
        {this.state.showBottom === 1 ? <BottomOne /> : <BotttomTwo />}

      </div>
    );
  }
}

export default App;

Answer 4

You can also directly use the components in the state and render them. Could be more flexible this way.

const BottomOne = () => <div>BottomOne</div>;
const BottomTwo = () => <div>BottomTwo</div>;

class Example extends React.Component {
  constructor() {
    super();
    this.state = { show: BottomOne };
    this.toggleComponent = this.toggleComponent.bind(this);
  }

  toggleComponent() {
    // Use whatever logic here to decide.
    let show = BottomOne;
    if (this.state.show === BottomOne) {
      show = BottomTwo;
    }

    this.setState({ show });
  }

  render() {
    return (
      <div>
        <button onClick={this.toggleComponent}>Change</button>
        <this.state.show />
      </div>
    );
  }
}

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

<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>