Don't always treat lowercase function with JSX as taking props

Author: joshwilsonvu

src/rules/reactivity.ts

@@ -379,7 +379,11 @@ const rule: TSESLint.RuleModule<MessageIds, []> = {
         const paramsNode = currentScopeNode.params[0];
         if (
           paramsNode?.type === "Identifier" &&
-          (currentScope().hasJSX || isPropsByName(paramsNode.name)) &&
+          ((currentScope().hasJSX &&
+            (currentScopeNode.type !== "FunctionDeclaration" ||
+              !currentScopeNode.id?.name?.match(/^[a-z]/))) ||
+            // begins with lowercase === not component
+            isPropsByName(paramsNode.name)) &&
           currentScopeNode.parent?.type !== "JSXExpressionContainer" // "render props" aren't components
         ) {
           // This function is a component, consider its parameter a props

test/rules/reactivity.test.ts

@@ -185,6 +185,11 @@ export const cases = run("reactivity", rule, {
     untrack(() => {
       console.log(signal());
     });`,
+    // has JSX, but lowercase function and not named props => don't treat first parameter as props
+    `function notAComponent(something) {
+      console.log(something.a);
+      return <div />;
+    }`,
   ],
   invalid: [
     // Untracked signals
@@ -241,6 +246,15 @@ export const cases = run("reactivity", rule, {
         },
       ],
     },
+    // treat first parameter of uppercase function with JSX as a props
+    {
+      code: `
+      function Component(something) {
+        console.log(something.a);
+        return <div />;
+      }`,
+      errors: [{ messageId: "untrackedReactive", type: T.MemberExpression }],
+    },
     // Derived signals
     {
       code: `