Exemple React-Transition-Group Transition (NodeJS)

L'objectif de la leçon
Créer un projet et installer la bibliothèque
L'exemple avec Transition simple
Exemple de Transition (unmountOnExit)

1. L'objectif de la leçon

La bibliothèque react-transition-group vous fournit des composants pour que vous puissiez créer des effets d'animation dans l'application React. La publication détaillée ci-dessous introduit de la bibliothèque, de ses composants qu'elle fournit, des API,..
Le Tutoriel de React-Transition-Group API

Dans cette leçon, je vais vous montrer quelques exemples avec les composants Transition& TransitionGroup fournis par la bibliothèque react-transition-group.

Un autre composant similaire est CSSTransition qui vous permet de travailler plus facilement avec CSS transition :

Exemple React-Transition-Group CSSTransition (NodeJS)

2. Créer un projet et installer la bibliothèque

Créez un projet React nommé transition-app en exécutant les commandes ci-dessous :

# Install 'create-react-app' tool (If it has never been installed)

npm install -g create-react-app

# Create project with 'create-react-app' tool:

create-react-app transition-app

Installer la bibliothèque react-transition-group :

# CD to your project

cd transition-app

# Install 'react-transition-group':

npm install react-transition-group --save

Exécutez votre application :

# Run app:

npm start

3. L'exemple avec Transition simple

Voici l'aperçu de cet exemple :

Lorsque la valeur de 'in' change de false à true, le composant <Transition> va changer en statut 'entering', et reste dans ce statut en 'timout' milisecondes, puis il change en statut 'entered'.
Lorsque la valeur de 'in' change de true à false, le composant <Transition> va changer en staut 'exiting', et reste dans ce statut en 'timout' milisecondes, puis il change en statut 'exited'.

OK, revenez au projet ci-dessus. Supprimez tout le contenu des fichiers App.js & App.css :

App.css

.my-msg {
   color: blue;
}

.my-msg-entering {
    color: blue;
    font-size: 150%;
    transition-duration: 1s;
 }

 .my-msg-entered {
    font-size: 150%;
    color: red;
 }

.my-msg-exiting {
    font-size: 100%;
    color: black;
    transition-duration: 1s;
}

.my-highlight  {
  color: red;
}

App.js

import React, { Component } from "react";
import logo from "./logo.svg";
import "./App.css";

import {
  TransitionGroup,
  CSSTransition,
  Transition
} from "react-transition-group";

class App extends React.Component {
  render() {
    return (
      <div>
        <MyComponent />
      </div>
    );
  }
}

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      stateOfIn: false,
      message: ""
    };
  }

  // Begin Enter: Do something here!
  onEnterHandler() {
    console.log("Begin Enter");
    this.setState({ message: "Begin Enter..." });
  }

  onEnteringHandler() {
    console.log("Entering... (Wait timeout!)");
    this.setState({ message: "Entering... (Wait timeout!)" });
  }

  onEnteredHandler() {
    console.log("OK Entered!");
    this.setState({ message: "OK Entered!" });
  }

  // Begin Exit: Do something here!
  onExitHandler() {
    console.log("Begin Exit");
    this.setState({ message: "Begin Exit..." });
  }

  onExitingHandler() {
    console.log("Exiting... (Wait timeout!)");
    this.setState({ message: "Exiting... (Wait timeout!)" });
  }

  onExitedHandler() {
    console.log("OK Exited!");
    this.setState({ message: "OK Exited!" });
  }

  render() {
    return (
      <div>
        <h3>&lt;Transition in={"{this.state.stateOfIn}"} &gt;</h3>

        <b>{"\u2728"} Focus on Textfield and see the effects:</b>
        <ul>
          <li className="my-highlight">
            Now 'in' = {String(this.state.stateOfIn)}
          </li>
          <li> false --&gt; true (Enter)</li>
          <li> true --&gt; false (Exit)</li>
        </ul>
        <div className="my-highlight">{this.state.message}</div>

        <br />

        <input
          type="text"
          onFocus={() => {
            this.setState({ stateOfIn: true });
          }}
          onBlur={() => {
            this.setState({ stateOfIn: false });
          }}
        />
        <br />

        <Transition
          in={this.state.stateOfIn}

          timeout={{ enter: 1500, exit: 2500 }}
          onEnter={() => this.onEnterHandler()}
          onEntering={() => this.onEnteringHandler()}
          onEntered={() => this.onEnteredHandler()}
          onExit={() => this.onExitHandler()}
          onExiting={() => this.onExitingHandler()}
          onExited={() => this.onExitedHandler()}
        >
        {(statusName) => (
           <div className={`my-msg my-msg-${statusName}`} >User name 2-20 characters</div>
        )}
        </Transition>
      </div>
    );
  }
}

export default App;

Il n'est pas nécessaire de changer les contenus du fichier index.js & index.html :

index.js

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import * as serviceWorker from './serviceWorker';

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

// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: http://bit.ly/CRA-PWA
serviceWorker.unregister();

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <meta name="theme-color" content="#000000">
    <link rel="manifest" href="%PUBLIC_URL%/manifest.json">
    <title>React CssTransition</title>
  </head>
  <body>
    <noscript>
      You need to enable JavaScript to run this app.
    </noscript>
    <div id="root"></div>
  </body>
</html>

Exemple 2 :

Avec toujours l'exemple ci-dessous, nous changez les contenus du App.css comme ci-dessous pour créer un effet plus complexe :

App.css (Edited) (2)

.my-msg {
   color: blue;
   margin-left: 300px;
   opacity: 0;
}

 .my-msg-entering {
    color: blue;
    margin-left: 0px;
    opacity: 1;
    font-size: 150%;
    transition-duration: 1s;
 }

 .my-msg-entered {
    opacity: 1;
    margin-left: 0px;
    font-size: 150%;
    color: red;
 }

.my-msg-exiting {
    opacity: 0;
    font-size: 100%;
    margin-left: 300px;
    color: black;
    transition-duration: 1s;
}

.my-highlight  {
  color: red;
}

4. Exemple de Transition (unmountOnExit)

<ReactTransitionGroup.Transition  unmountOnExit = {true/false} mountOnEnter = {true/false}>

    <!-- Child Component -->
    <MySingleElement>
       <MyOtherElements />
    </MySingleElement>

</ReactTransitionGroup.Transition>

L'avant-première de cet exemple :

App3.css

.my-msg-entering {
    color: blue;
 }

 .my-msg-entered {
    color: red;
 }

.my-highlight  {
  color: red;
}

App3.js

import React, { Component } from "react";
import logo from "./logo.svg";
import "./App3.css";

import {
  TransitionGroup,
  CSSTransition,
  Transition
} from "react-transition-group";

class App extends React.Component {
  render() {
    return (
      <div>
        <MyComponent />
      </div>
    );
  }
}

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      stateOfIn: false,
      message: ""
    };
  }

  // Begin Enter: Do anything!
  onEnterHandler() {
    console.log("Begin Enter");
    this.setState({ message: "Begin Enter..." });
  }

  onEnteringHandler() {
    console.log("Entering... (Wait timeout!)");
    this.setState({ message: "Entering... (Wait timeout!)" });
  }

  onEnteredHandler() {
    console.log("OK Entered!");
    this.setState({ message: "OK Entered!" });
  }

  // Begin Exit: Do anything!
  onExitHandler() {
    console.log("Begin Exit");
    this.setState({ message: "Begin Exit..." });
  }

  onExitingHandler() {
    console.log("Exiting... (Wait timeout!)");
    this.setState({ message: "Exiting... (Wait timeout!)" });
  }

  onExitedHandler() {
    console.log("OK Exited!");
    this.setState({ message: "OK Exited!" });
  }

  render() {
    return (
      <div>
        <h3>&lt;Transition in={"{this.state.stateOfIn}"} &gt;</h3>

        <b>{"\u2728"} Click the buttons and see the effects:</b>
        <ul>
          <li className="my-highlight">
            Now 'in' = {String(this.state.stateOfIn)}
          </li>
          <li> false --&gt; true (Enter)</li>
          <li> true --&gt; false (Exit)</li>
        </ul>
        <div className="my-highlight">{this.state.message}</div>

        <br />

        <input
          type="text"
          onFocus={() => {
            this.setState({ stateOfIn: true });
          }}
          onBlur={() => {
            this.setState({ stateOfIn: false });
          }}
        />
        <br />

        <Transition
          in={this.state.stateOfIn}

          unmountOnExit

          timeout={{ enter: 1500, exit: 2500 }}
          onEnter={() => this.onEnterHandler()}
          onEntering={() => this.onEnteringHandler()}
          onEntered={() => this.onEnteredHandler()}
          onExit={() => this.onExitHandler()}
          onExiting={() => this.onExitingHandler()}
          onExited={() => this.onExitedHandler()}
        >
          {stateName => {
            // stateName: 'entering', 'enterd', 'exiting', 'exited'
            switch (stateName) {

              case "entering":
                return (
                  <b className="my-msg-entering">
                    ⭐ Note: User name 2-20 characters
                  </b>
                );
              case "entered":
                return (
                  <b className="my-msg-entered">
                    ⭐ Note: User name 2-20 characters
                  </b>
                );
              case "exiting":
                return <div>(User Name)</div>;
              case "exited":
                return <b>(User Name)</b>;
              default:
                return <div>??</div>;
            }
          }}
        </Transition>
      </div>
    );
  }
}

export default App;

Changez le contenu du fichier index.js :