CSSTransition.js

import * as PropTypes from 'prop-types';
import addOneClass from 'dom-helpers/class/addClass';

import removeOneClass from 'dom-helpers/class/removeClass';
import React from 'react';

import Transition from './Transition';
import { classNamesShape } from './utils/PropTypes';

const addClass = (node, classes) => node && classes && classes.split(' ').forEach(c => addOneClass(node, c));
const removeClass = (node, classes) => node && classes && classes.split(' ').forEach(c => removeOneClass(node, c));

/**
 * A transition component inspired by the excellent
 * [ng-animate](http://www.nganimate.org/) library, you should use it if you're
 * using CSS transitions or animations. It's built upon the
 * [`Transition`](https://reactcommunity.org/react-transition-group/transition)
 * component, so it inherits all of its props.
 *
 * `CSSTransition` applies a pair of class names during the `appear`, `enter`,
 * and `exit` states of the transition. The first class is applied and then a
 * second `*-active` class in order to activate the CSSS transition. After the
 * transition, matching `*-done` class names are applied to persist the
 * transition state.
 *
 * ```jsx
 * function App() {
 *   const [inProp, setInProp] = useState(false);
 *   return (
 *     <div>
 *       <CSSTransition in={inProp} timeout={200} classNames="my-node">
 *         <div>
 *           {"I'll receive my-node-* classes"}
 *         </div>
 *       </CSSTransition>
 *       <button type="button" onClick={() => setInProp(true)}>
 *         Click to Enter
 *       </button>
 *     </div>
 *   );
 * }
 * ```
 *
 * When the `in` prop is set to `true`, the child component will first receive
 * the class `example-enter`, then the `example-enter-active` will be added in
 * the next tick. `CSSTransition` [forces a
 * reflow](https://github.com/reactjs/react-transition-group/blob/5007303e729a74be66a21c3e2205e4916821524b/src/CSSTransition.js#L208-L215)
 * between before adding the `example-enter-active`. This is an important trick
 * because it allows us to transition between `example-enter` and
 * `example-enter-active` even though they were added immediately one after
 * another. Most notably, this is what makes it possible for us to animate
 * _appearance_.
 *
 * ```css
 * .my-node-enter {
 *   opacity: 0;
 * }
 * .my-node-enter-active {
 *   opacity: 1;
 *   transition: opacity 200ms;
 * }
 * .my-node-exit {
 *   opacity: 1;
 * }
 * .my-node-exit-active {
 *   opacity: 0;
 *   transition: opacity 200ms;
 * }
 * ```
 *
 * `*-active` classes represent which styles you want to animate **to**.
 */
class CSSTransition extends React.Component {
  static defaultProps = {
    classNames: ''
  }
  onEnter = (node, appearing) => {
    const { className } = this.getClassNames(appearing ? 'appear' : 'enter')

    this.removeClasses(node, 'exit');
    addClass(node, className)

    if (this.props.onEnter) {
      this.props.onEnter(node, appearing)
    }
  }

  onEntering = (node, appearing) => {
    const { activeClassName } = this.getClassNames(
      appearing ? 'appear' : 'enter'
    );

    this.reflowAndAddClass(node, activeClassName)

    if (this.props.onEntering) {
      this.props.onEntering(node, appearing)
    }
  }

  onEntered = (node, appearing) => {
    const appearClassName = this.getClassNames('appear').doneClassName;
    const enterClassName = this.getClassNames('enter').doneClassName;
    const doneClassName = appearing
      ? `${appearClassName} ${enterClassName}`
      : enterClassName;

    this.removeClasses(node, appearing ? 'appear' : 'enter');
    addClass(node, doneClassName);

    if (this.props.onEntered) {
      this.props.onEntered(node, appearing)
    }
  }

  onExit = (node) => {
    const { className } = this.getClassNames('exit')

    this.removeClasses(node, 'appear');
    this.removeClasses(node, 'enter');
    addClass(node, className)

    if (this.props.onExit) {
      this.props.onExit(node)
    }
  }

  onExiting = (node) => {
    const { activeClassName } = this.getClassNames('exit')

    this.reflowAndAddClass(node, activeClassName)

    if (this.props.onExiting) {
      this.props.onExiting(node)
    }
  }

  onExited = (node) => {
    const { doneClassName } = this.getClassNames('exit');

    this.removeClasses(node, 'exit');
    addClass(node, doneClassName);

    if (this.props.onExited) {
      this.props.onExited(node)
    }
  }

  getClassNames = (type) => {
    const { classNames } = this.props;
    const isStringClassNames = typeof classNames === 'string';
    const prefix = isStringClassNames && classNames ? classNames + '-' : '';

    let className = isStringClassNames ?
      prefix + type : classNames[type]

    let activeClassName = isStringClassNames ?
      className + '-active' : classNames[type + 'Active'];

    let doneClassName = isStringClassNames ?
      className + '-done' : classNames[type + 'Done'];

    return {
      className,
      activeClassName,
      doneClassName
    };
  }

  removeClasses(node, type) {
    const { className, activeClassName, doneClassName } = this.getClassNames(type)
    className && removeClass(node, className);
    activeClassName && removeClass(node, activeClassName);
    doneClassName && removeClass(node, doneClassName);
  }

  reflowAndAddClass(node, className) {
    // This is for to force a repaint,
    // which is necessary in order to transition styles when adding a class name.
    if (className) {
      /* eslint-disable no-unused-expressions */
      node && node.scrollTop;
      /* eslint-enable no-unused-expressions */
      addClass(node, className);
    }
  }

  render() {
    const props = { ...this.props };

    delete props.classNames;

    return (
      <Transition
        {...props}
        onEnter={this.onEnter}
        onEntered={this.onEntered}
        onEntering={this.onEntering}
        onExit={this.onExit}
        onExiting={this.onExiting}
        onExited={this.onExited}
      />
    );
  }
}

CSSTransition.propTypes = {
  ...Transition.propTypes,

  /**
   * The animation classNames applied to the component as it enters, exits or
   * has finished the transition. A single name can be provided and it will be
   * suffixed for each stage: e.g.
   *
   * `classNames="fade"` applies `fade-enter`, `fade-enter-active`,
   * `fade-enter-done`, `fade-exit`, `fade-exit-active`, `fade-exit-done`,
   * `fade-appear`, `fade-appear-active`, and `fade-appear-done`.
   *
   * **Note**: `fade-appear-done` and `fade-enter-done` will _both_ be applied.
   * This allows you to define different behavior for when appearing is done and
   * when regular entering is done, using selectors like
   * `.fade-enter-done:not(.fade-appear-done)`. For example, you could apply an
   * epic entrance animation when element first appears in the DOM using
   * [Animate.css](https://daneden.github.io/animate.css/). Otherwise you can
   * simply use `fade-enter-done` for defining both cases.
   *
   * Each individual classNames can also be specified independently like:
   *
   * ```js
   * classNames={{
   *  appear: 'my-appear',
   *  appearActive: 'my-active-appear',
   *  appearDone: 'my-done-appear',
   *  enter: 'my-enter',
   *  enterActive: 'my-active-enter',
   *  enterDone: 'my-done-enter',
   *  exit: 'my-exit',
   *  exitActive: 'my-active-exit',
   *  exitDone: 'my-done-exit',
   * }}
   * ```
   *
   * If you want to set these classes using CSS Modules:
   *
   * ```js
   * import styles from './styles.css';
   * ```
   *
   * you might want to use camelCase in your CSS file, that way could simply
   * spread them instead of listing them one by one:
   *
   * ```js
   * classNames={{ ...styles }}
   * ```
   *
   * @type {string | {
   *  appear?: string,
   *  appearActive?: string,
   *  appearDone?: string,
   *  enter?: string,
   *  enterActive?: string,
   *  enterDone?: string,
   *  exit?: string,
   *  exitActive?: string,
   *  exitDone?: string,
   * }}
   */
  classNames: classNamesShape,

  /**
   * A `<Transition>` callback fired immediately after the 'enter' or 'appear' class is
   * applied.
   *
   * @type Function(node: HtmlElement, isAppearing: bool)
   */
  onEnter: PropTypes.func,

  /**
   * A `<Transition>` callback fired immediately after the 'enter-active' or
   * 'appear-active' class is applied.
   *
   * @type Function(node: HtmlElement, isAppearing: bool)
   */
  onEntering: PropTypes.func,

  /**
   * A `<Transition>` callback fired immediately after the 'enter' or
   * 'appear' classes are **removed** and the `done` class is added to the DOM node.
   *
   * @type Function(node: HtmlElement, isAppearing: bool)
   */
  onEntered: PropTypes.func,

  /**
   * A `<Transition>` callback fired immediately after the 'exit' class is
   * applied.
   *
   * @type Function(node: HtmlElement)
   */
  onExit: PropTypes.func,

  /**
   * A `<Transition>` callback fired immediately after the 'exit-active' is applied.
   *
   * @type Function(node: HtmlElement)
   */
  onExiting: PropTypes.func,

  /**
   * A `<Transition>` callback fired immediately after the 'exit' classes
   * are **removed** and the `exit-done` class is added to the DOM node.
   *
   * @type Function(node: HtmlElement)
   */
  onExited: PropTypes.func,
};

export default CSSTransition