Merge pull request #239 from kinyaying/master

Update typechecking-with-proptypes.md

content/docs/typechecking-with-proptypes.md

@@ -168,4 +168,20 @@ ReactDOM.render(
 );
 ```
 
+If you are using a Babel transform like [transform-class-properties](https://babeljs.io/docs/plugins/transform-class-properties/) , you can also declare `defaultProps` as static property within a React component class. This syntax has not yet been finalized though and will require a compilation step to work within a browser. For more information, see the [class fields proposal](https://github.com/tc39/proposal-class-fields).
+
+```javascript
+class Greeting extends React.Component {
+  static defaultProps = {
+    name: 'stranger'
+  }
+
+  render() {
+    return (
+      <div>Hello, {this.props.name}</div>
+    )
+  }
+}
+```
+
 The `defaultProps` will be used to ensure that `this.props.name` will have a value if it was not specified by the parent component. The `propTypes` typechecking happens after `defaultProps` are resolved, so typechecking will also apply to the `defaultProps`.