render only children with component=null (reactjs#243)

* render only children with component=null

* update jsdocs for component=null

* lint

Author: mattkrick

src/TransitionGroup.js

@@ -9,6 +9,9 @@ const propTypes = {
   /**
    * `<TransitionGroup>` renders a `<div>` by default. You can change this
    * behavior by providing a `component` prop.
+   * If you use React v16+ and would like to avoid a wrapping `<div>` element
+   * you can pass in `component={null}`. This is useful if the wrapping div
+   * borks your css styles.
    */
   component: PropTypes.any,
   /**
@@ -179,15 +182,18 @@ class TransitionGroup extends React.Component {
 
   render() {
     const { component: Component, childFactory, ...props } = this.props;
-    const { children } = this.state;
+    const children = values(this.state.children).map(childFactory);
 
     delete props.appear;
     delete props.enter;
     delete props.exit;
 
+    if (Component === null) {
+      return children;
+    }
     return (
       <Component {...props}>
-        {values(children).map(childFactory)}
+        {children}
       </Component>
     );
   }

yarn.lock

@@ -5773,12 +5773,20 @@ promise@^7.1.1:
   dependencies:
     asap "~2.0.3"
 
-prop-types@15.5.8, prop-types@^15.5.10, prop-types@^15.5.4, prop-types@^15.5.6, prop-types@^15.5.8, prop-types@^15.5.9, prop-types@^15.6.0:
+prop-types@15.5.8, prop-types@^15.5.4, prop-types@^15.5.6, prop-types@^15.5.8:
   version "15.5.8"
   resolved "https://registry.yarnpkg.com/prop-types/-/prop-types-15.5.8.tgz#6b7b2e141083be38c8595aa51fc55775c7199394"
   dependencies:
     fbjs "^0.8.9"
 
+prop-types@^15.5.10, prop-types@^15.5.9, prop-types@^15.6.0:
+  version "15.6.0"
+  resolved "https://registry.yarnpkg.com/prop-types/-/prop-types-15.6.0.tgz#ceaf083022fc46b4a35f69e13ef75aed0d639856"
+  dependencies:
+    fbjs "^0.8.16"
+    loose-envify "^1.3.1"
+    object-assign "^4.1.1"
+
 proxy-addr@~2.0.2:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/proxy-addr/-/proxy-addr-2.0.2.tgz#6571504f47bb988ec8180253f85dd7e14952bdec"