Fix class properties retrieval in prefer-stateless-function (fixes #499)

Author: yannickcr

lib/rules/prefer-stateless-function.js

@@ -43,6 +43,7 @@ module.exports = Components.detect(function(context, components, utils) {
    */
   function getComponentProperties(node) {
     switch (node.type) {
+      case 'ClassExpression':
       case 'ClassDeclaration':
         return node.body.body;
       case 'ObjectExpression':

tests/lib/rules/prefer-stateless-function.js

@@ -179,6 +179,18 @@ ruleTester.run('prefer-stateless-function', rule, {
         '});'
       ].join('\n'),
       parserOptions: parserOptions
+    }, {
+      code: [
+        'export default (Component) => (',
+        '  class Test extends React.Component {',
+        '    componentDidMount() {}',
+        '    render() {',
+        '      return <Component />;',
+        '    }',
+        '  }',
+        ');'
+      ].join('\n'),
+      parser: 'babel-eslint'
     }
   ],