Fixes

src/CSSTransition.js

@@ -191,7 +191,7 @@ class CSSTransition extends React.Component {
     const { className } = this.getClassNames('exit')
 
     this.removeClasses(node, 'appear');
-    this.removeClasses(node, 'exit');
+    this.removeClasses(node, 'enter');
     addClass(node, className)
 
     if (this.props.onExit) {

src/Transition.js

@@ -13,7 +13,7 @@ export const EXITING = 'exiting';
 /**
  * The Transition component lets you describe a transition from one component
  * state to another _over time_ with a simple declarative API. Most commonly
- * It's used to animate the mounting and unmounting of Component, but can also
+ * it's used to animate the mounting and unmounting of a component, but can also
  * be used to describe in-place transition states as well.
  *
  * By default the `Transition` component does not alter the behavior of the
@@ -50,6 +50,22 @@ export const EXITING = 'exiting';
  * );
  * ```
  *
+ * As noted the `Transition` component doesn't _do_ anything by itself to its child component.
+ * What it does do is track transition states over time so you can adjust you
+ * component (such as adding styles of classes) as it changes states.
+ *
+ * There are 4 main states a Transition can be in:
+ *  - `ENTERING`
+ *  - `ENTERED`
+ *  - `EXITING`
+ *  - `EXITED`
+ *
+ * Transition state is toggled via the `in` prop. When `true` the component begins the
+ * "Enter" stage. During this stage, the component will shift from its current transitions state,
+ * to `'entering'` for the duration of the transition and then to the `'entered'` stage once
+ * it's complete. So in the following example: `<Transition in timeout={500} />`,
+ * the component will immediately shift to `'entering'` and stay there for 500ms and switch to `'entered'`.
+ * When `in` is `false` the same thing happens except the states are `'exiting'` to `'exited'`.
  */
 class Transition extends React.Component {
   static contextTypes = {
@@ -280,10 +296,7 @@ class Transition extends React.Component {
 
 Transition.propTypes = {
   /**
-   * Generally a React element to animate, all unknown props on Transition are
-   * transfered to the **single** child element.
-   *
-   * For advanced uses a `function` child can be used instead of a React element.
+   * A `function` child can be used instead of a React element.
    * This function is called with the current transition status
    * ('entering', 'entered', 'exiting', 'exited', 'unmounted'), which can used
    * to apply context specific props to a component.
@@ -307,17 +320,25 @@ Transition.propTypes = {
   in: PropTypes.bool,
 
   /**
-   * Wait until the first "enter" transition to mount the component (add it to the DOM)
+   * By default the child component is mounted immediately along with
+   * the parent `Transition` component. If you want to "lazy mount" the component on the
+   * first `in={true}` you can set `mountOnEnter`. After the first enter transition the component will stay
+   * mounted even on exit unless you also specify `unmountOnExit`
    */
   mountOnEnter: PropTypes.bool,
 
   /**
-   * Unmount the component (remove it from the DOM) when it is not shown
+   * By default the child component is mounted in the DOM after it enteres the `'exited'` state.
+   * If you'd prefer to completely unmonut the component after it exits, set `unmountOnExit`.
    */
   unmountOnExit: PropTypes.bool,
 
   /**
-   * Enable or disable appear (entering on mount) transitions.
+   * Normally a component is not transitioned on it's initial mount. If you
+   * want to transition on the first mount set `appear` to `true`, and the
+   * component will enter the component.
+   *
+   * > Note: there are no specific "appear" states. `apprear` only an additional `enter` transition.
    */
   appear: PropTypes.bool,
 
@@ -363,44 +384,47 @@ Transition.propTypes = {
   addEndListener: PropTypes.func,
 
   /**
-   * Callback fired before the "entering" status is applied.
+   * Callback fired before the "entering" status is applied. An extra parameter
+   * `isAppearing` is supplied to indicate if the enter stage is occuring on the initial mount
    *
-   * @type Function(node: HtmlElement, isAppearing: bool)
+   * @type Function(node: HtmlElement, isAppearing: bool) -> void
    */
   onEnter: PropTypes.func,
 
   /**
-   * Callback fired after the "entering" status is applied.
+   * Callback fired after the "entering" status is applied. An extra parameter
+   * `isAppearing` is supplied to indicate if the enter stage is occuring on the initial mount
    *
    * @type Function(node: HtmlElement, isAppearing: bool)
    */
   onEntering: PropTypes.func,
 
   /**
-   * Callback fired after the "enter" status is applied.
+   * Callback fired after the "enter" status is applied. An extra parameter
+   * `isAppearing` is supplied to indicate if the enter stage is occuring on the initial mount
    *
-   * @type Function(node: HtmlElement, isAppearing: bool)
+   * @type Function(node: HtmlElement, isAppearing: bool) -> void
    */
   onEntered: PropTypes.func,
 
   /**
    * Callback fired before the "exiting" status is applied.
    *
-   * @type Function(node: HtmlElement)
+   * @type Function(node: HtmlElement) -> void
    */
   onExit: PropTypes.func,
 
   /**
    * Callback fired after the "exiting" status is applied.
    *
-   * @type Function(node: HtmlElement)
+   * @type Function(node: HtmlElement) -> void
    */
   onExiting: PropTypes.func,
 
   /**
    * Callback fired after the "exited" status is applied.
    *
-   * @type Function(node: HtmlElement)
+   * @type Function(node: HtmlElement) -> void
    */
   onExited: PropTypes.func,
 };

src/TransitionGroup.js

@@ -37,10 +37,23 @@ const propTypes = {
    * on individual children Transitions.
    */
   exit: PropTypes.bool,
+
+  /**
+   * You may need to apply reactive updates to a child as it is exiting.
+   * This is generally done by using `cloneElement` however in the case of an exiting
+   * child the element has already been removed and not accessible to the consumer.
+   *
+   * If you do need to update a child as it leaves you can provide a `childFactory`
+   * to wrap every child, even the ones that are leaving.
+   *
+   * @type Function(child: ReactElement) -> ReactElement
+   */
+  childFactory: PropTypes.func,
 };
 
 const defaultProps = {
   component: 'div',
+  childFactory: child => child,
 };
 
 /**
@@ -111,11 +124,8 @@ class TransitionGroup extends React.Component {
     // Initial children should all be entering, dependent on appear
     this.state = {
       children: getChildMapping(props.children, child => {
-        const onExited = () => {
-          if (child.props.onExited)
-            child.props.onExited();
-
-          this.handleExited(child.key);
+        const onExited = (node) => {
+          this.handleExited(child.key, node, child.props.onExited);
         }
 
         return cloneElement(child, {
@@ -156,7 +166,9 @@ class TransitionGroup extends React.Component {
 
       if (!isValidElement(child)) return;
 
-      const onExited = () => this.handleExited(key);
+      const onExited = (node) => {
+        this.handleExited(child.key, node, child.props.onExited);
+      }
 
       const hasPrev = key in prevChildMapping;
       const hasNext = key in nextChildMapping;
@@ -195,20 +207,24 @@ class TransitionGroup extends React.Component {
     this.setState({ children });
   }
 
-  handleExited = (key) => {
+  handleExited = (key, node, originalHandler) => {
     let currentChildMapping = getChildMapping(this.props.children);
 
     if (key in currentChildMapping) return
 
+    if (originalHandler)
+      originalHandler(node)
+
     this.setState((state) => {
       let children = { ...state.children };
+
       delete children[key];
       return { children };
     });
   };
 
   render() {
-    const { component: Component, ...props } = this.props;
+    const { component: Component, childFactory, ...props } = this.props;
     const { children } = this.state;
 
     delete props.appear;
@@ -217,7 +233,7 @@ class TransitionGroup extends React.Component {
 
     return (
       <Component {...props}>
-        {values(children)}
+        {values(children).map(childFactory)}
       </Component>
     );
   }

www/package.json

@@ -13,14 +13,13 @@
   "license": "MIT",
   "dependencies": {
     "bootstrap": "^4.0.0-alpha.6",
-    "gatsby": "^1.0.0-beta.7",
-    "gatsby-link": "^1.0.0-beta.6",
-    "gatsby-plugin-sass": "^1.0.0-beta.1",
-    "gatsby-remark-prismjs": "^1.0.0-beta.6",
-    "gatsby-source-filesystem": "^1.0.0-beta.6",
-    "gatsby-transformer-react-docgen": "^1.0.0-beta.6",
-    "gatsby-transformer-remark": "^1.0.0-beta.6",
-    "graphql-type-json": "^0.1.4",
+    "gatsby": "^1.0.0",
+    "gatsby-link": "^1.0.0",
+    "gatsby-plugin-sass": "^1.0.0",
+    "gatsby-remark-prismjs": "^1.0.0",
+    "gatsby-source-filesystem": "^1.0.0",
+    "gatsby-transformer-react-docgen": "^1.0.0",
+    "gatsby-transformer-remark": "^1.0.0",
     "lodash": "^4.17.4"
   },
   "devDependencies": {