[eslint-plugin-react-hooks] Fixed crash when referencing arguments in arrow functions. (facebook#16356)

hristo-kanchev · gaearon · commit 9e64bf18e118 · 2019-08-14T14:44:06.000+01:00
* Fixed issue with def being undefined while referencing arguments.

* Removed todo comment.

* Skip exhaustive deps check if def is null.

* Fixed code formatting in ExhaustiveDeps.

* Removed unneeded comment in ExhaustiveDeps.
diff --git a/packages/eslint-plugin-react-hooks/__tests__/ESLintRuleExhaustiveDeps-test.js b/packages/eslint-plugin-react-hooks/__tests__/ESLintRuleExhaustiveDeps-test.js
@@ -1023,6 +1023,28 @@ const tests = {
         }
       `,
     },
+    // Ignore arguments keyword for arrow functions.
+    {
+      code: `
+        function Example() {
+          useEffect(() => {
+            arguments
+          }, [])
+        }
+      `,
+    },
+    {
+      code: `
+        function Example() {
+          useEffect(() => {
+            const bar = () => {
+              arguments;
+            };
+            bar();
+          }, [])
+        }
+      `,
+    },
   ],
   invalid: [
     {
diff --git a/packages/eslint-plugin-react-hooks/src/ExhaustiveDeps.js b/packages/eslint-plugin-react-hooks/src/ExhaustiveDeps.js
@@ -397,13 +397,14 @@ export default {
             });
           }
 
-          // Ignore references to the function itself as it's not defined yet.
           const def = reference.resolved.defs[0];
-          if (
-            def != null &&
-            def.node != null &&
-            def.node.init === node.parent
-          ) {
+
+          if (def == null) {
+            continue;
+          }
+
+          // Ignore references to the function itself as it's not defined yet.
+          if (def.node != null && def.node.init === node.parent) {
             continue;
           }
 
