Fix prefer-stateless-function for conditional JSX (fixes #516)

Author: yannickcr

lib/rules/prefer-stateless-function.js

@@ -209,7 +209,7 @@ module.exports = Components.detect(function(context, components, utils) {
         }
         scope = scope.upper;
       }
-      if (!blockNode || !blockNode.key || blockNode.key.name !== 'render' || utils.isReturningJSX(node)) {
+      if (!blockNode || !blockNode.key || blockNode.key.name !== 'render' || utils.isReturningJSX(node, true)) {
         return;
       }
       markReturnAsInvalid(node);

lib/util/Components.js

@@ -166,9 +166,10 @@ function componentRule(rule, context) {
      * Check if the node is returning JSX
      *
      * @param {ASTNode} node The AST node being checked (can be a ReturnStatement or an ArrowFunctionExpression).
+     * @param {Boolean} strict If true, in a ternary condition the node must return JSX in both cases
      * @returns {Boolean} True if the node is returning JSX, false if not
      */
-    isReturningJSX: function(node) {
+    isReturningJSX: function(node, strict) {
       var property;
       switch (node.type) {
         case 'ReturnStatement':
@@ -191,6 +192,10 @@ function componentRule(rule, context) {
         node[property].type === 'ConditionalExpression' &&
         node[property].alternate.type === 'JSXElement'
       ;
+      var returnsConditionalJSX =
+        strict ? (returnsConditionalJSXConsequent && returnsConditionalJSXAlternate) :
+        (returnsConditionalJSXConsequent || returnsConditionalJSXAlternate);
+
       var returnsJSX =
         node[property] &&
         node[property].type === 'JSXElement'
@@ -203,8 +208,7 @@ function componentRule(rule, context) {
       ;
 
       return Boolean(
-        returnsConditionalJSXConsequent ||
-        returnsConditionalJSXAlternate ||
+        returnsConditionalJSX ||
         returnsJSX ||
         returnsReactCreateElement
       );