Fix #518: Exclude generic function in TSX file

src/noFunctionExpressionRule.ts

@@ -33,27 +33,48 @@ export class Rule extends Lint.Rules.AbstractRule {
 }
 
 class NoFunctionExpressionRuleWalker extends ErrorTolerantWalker {
+    private allowGenericFunctionExpression: boolean = false;
+
+    constructor(sourceFile: ts.SourceFile, options: Lint.IOptions) {
+        super(sourceFile, options);
+        if (sourceFile.fileName.endsWith('tsx')) {
+            this.allowGenericFunctionExpression = true;
+        }
+    }
+
     protected visitFunctionExpression(node: ts.FunctionExpression): void {
         const walker = new SingleFunctionWalker(this.getSourceFile(), this.getOptions());
         node.getChildren().forEach((child: ts.Node) => {
             walker.walk(child);
         });
+
+        const isGenericFunctionInTSX = this.allowGenericFunctionExpression && walker.isGenericFunction;
         // function expression that access 'this' is allowed
-        if (!walker.isAccessingThis && !node.asteriskToken) {
+        if (!walker.isAccessingThis && !node.asteriskToken
+            // generic function expression in .tsx file is allowed
+            && !isGenericFunctionInTSX) {
             this.addFailureAt(node.getStart(), node.getWidth(), Rule.FAILURE_STRING);
         }
+
         super.visitFunctionExpression(node);
     }
 }
 
 class SingleFunctionWalker extends ErrorTolerantWalker {
     public isAccessingThis: boolean = false;
+    public isGenericFunction: boolean = false;
     protected visitNode(node: ts.Node): void {
         if (node.getText() === 'this') {
             this.isAccessingThis = true;
         }
         super.visitNode(node);
     }
+
+    protected visitTypeReference(node: ts.TypeReferenceNode): void {
+        this.isGenericFunction = true;
+        super.visitTypeReference(node);
+    }
+
     /* tslint:disable:no-empty */
     protected visitFunctionExpression(): void {
         // do not visit inner blocks
@@ -62,4 +83,4 @@ class SingleFunctionWalker extends ErrorTolerantWalker {
         // do not visit inner blocks
     }
     /* tslint:enable:no-empty */
-}
+}

src/tests/NoFunctionExpressionRuleTests.ts

@@ -43,6 +43,22 @@ describe('noFunctionExpressionRule', (): void => {
         TestHelper.assertViolations(ruleName, script, []);
     });
 
+    it('should fail on not generic type function expression and pass generic type function within a .tsx file', (): void => {
+        TestHelper.assertViolations(
+            ruleName,
+            "test-data/NoFunctionExpressionWithInTSX.tsx",
+            [{
+                "failure": "Use arrow function instead of function expression",
+                "name": "test-data/NoFunctionExpressionWithInTSX.tsx",
+                "ruleName": "no-function-expression",
+                "startPosition": {
+                    "character": 28,
+                    "line": 1
+                }
+            }],
+        );
+    });
+
     it('should fail on function expression', (): void => {
         const script: string = `
             var x = function() {
@@ -94,4 +110,4 @@ describe('noFunctionExpressionRule', (): void => {
             }
         ]);
     });
-});
+});

test-data/NoFunctionExpressionWithInTSX.tsx

@@ -0,0 +1,7 @@
+const notGenericFunction = function() {
+  return 1 + 1;
+};
+
+const genericFunction = function<T>(x: T): T {
+  return x;
+};