Check if SFC is returning JSX or null

Author: jomasti

lib/util/Components.js

@@ -303,14 +303,7 @@ function componentRule(rule, context) {
       return calledOnReact;
     },
 
-    /**
-     * Check if the node is returning JSX
-     *
-     * @param {ASTNode} ASTnode The AST node being checked
-     * @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(ASTnode, strict) {
+    getReturnPropertyAndNode(ASTnode) {
       let property;
       let node = ASTnode;
       switch (node.type) {
@@ -321,19 +314,34 @@ function componentRule(rule, context) {
           property = 'body';
           if (node[property] && node[property].type === 'BlockStatement') {
             node = utils.findReturnStatement(node);
-            if (!node) {
-              return false;
-            }
             property = 'argument';
           }
           break;
         default:
           node = utils.findReturnStatement(node);
-          if (!node) {
-            return false;
-          }
           property = 'argument';
       }
+      return {
+        node: node,
+        property: property
+      };
+    },
+
+    /**
+     * Check if the node is returning JSX
+     *
+     * @param {ASTNode} ASTnode The AST node being checked
+     * @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(ASTnode, strict) {
+      const nodeAndProperty = utils.getReturnPropertyAndNode(ASTnode);
+      const node = nodeAndProperty.node;
+      const property = nodeAndProperty.property;
+
+      if (!node) {
+        return false;
+      }
 
       const returnsConditionalJSXConsequent =
         node[property] &&
@@ -363,6 +371,35 @@ function componentRule(rule, context) {
       );
     },
 
+    /**
+     * Check if the node is returning null
+     *
+     * @param {ASTNode} ASTnode The AST node being checked
+     * @returns {Boolean} True if the node is returning null, false if not
+     */
+    isReturningNull(ASTnode) {
+      const nodeAndProperty = utils.getReturnPropertyAndNode(ASTnode);
+      const property = nodeAndProperty.property;
+      const node = nodeAndProperty.node;
+
+      if (!node) {
+        return false;
+      }
+
+      return node[property] && node[property].value === null;
+    },
+
+    /**
+     * Check if the node is returning JSX or null
+     *
+     * @param {ASTNode} ASTnode The AST node being checked
+     * @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 or null, false if not
+     */
+    isReturningJSXOrNull(ASTNode, strict) {
+      return utils.isReturningJSX(ASTNode, strict) || utils.isReturningNull(ASTNode);
+    },
+
     /**
      * Find a return statment in the current node
      *
@@ -437,7 +474,7 @@ function componentRule(rule, context) {
           return null;
         }
         // Return the node if it is a function that is not a class method and is not inside a JSX Element
-        if (isFunction && !isMethod && !isJSXExpressionContainer && utils.isReturningJSX(node)) {
+        if (isFunction && !isMethod && !isJSXExpressionContainer && utils.isReturningJSXOrNull(node)) {
           return node;
         }
         scope = scope.upper;

tests/lib/rules/no-this-in-sfc.js

@@ -33,6 +33,11 @@ ruleTester.run('no-this-in-sfc', rule, {
       const { foo } = props;
       return <div bar={foo} />;
     }`
+  }, {
+    code: `
+    function Foo({ foo }) {
+      return <div bar={foo} />;
+    }`
   }, {
     code: `
     class Foo extends React.Component {
@@ -58,7 +63,7 @@ ruleTester.run('no-this-in-sfc', rule, {
     settings: {react: {createClass: 'createClass'}}
   }, {
     code: `
-    function Foo (bar) {
+    function foo(bar) {
       this.bar = bar;
       this.props = 'baz';
       this.getFoo = function() {