fix(require-throws): arrow function expressions should check body o…

…nly; fixes #597

`node.expression` is just a boolean with `ArrowFunctionExpression` (and `false` on `FunctionExpression`, `FunctionDeclaration`).

Also avoids reporting nested throw statements (which might not be invoked as the function executes).

README.md

@@ -13210,6 +13210,18 @@ function quux () {
 }
 // Settings: {"jsdoc":{"tagNamePreference":{"throws":false}}}
 // Message: Unexpected tag `@throws`
+
+/**
+ *
+ */
+const itself = (b) => {
+  const a = () => {};
+  if (b) {
+    throw new Error('oops')
+  }
+  return a;
+};
+// Message: Missing JSDoc @throws declaration.
 ````
 
 The following patterns are not considered problems:
@@ -13258,6 +13270,16 @@ function quux () {
   throw new Error('err')
 }
 // Options: [{"exemptedBy":["type"]}]
+
+/**
+ *
+ */
+const itself = (n) => n;
+
+/**
+ * Not tracking on nested function
+ */
+const itself = () => () => {throw new Error('oops');};
 ````
 
 

src/jsdocUtils.js

@@ -614,17 +614,18 @@ const hasReturnValue = (node) => {
  * Checks if a node has a throws statement.
  *
  * @param {object} node
+ * @param {boolean} innerFunction
  * @returns {boolean}
  */
-const hasThrowValue = (node) => {
+const hasThrowValue = (node, innerFunction) => {
   if (!node) {
     return false;
   }
   switch (node.type) {
   case 'FunctionExpression':
   case 'FunctionDeclaration':
   case 'ArrowFunctionExpression': {
-    return node.expression || hasThrowValue(node.body);
+    return !innerFunction && hasThrowValue(node.body, true);
   }
   case 'BlockStatement': {
     return node.body.some((bodyNode) => {

test/rules/assertions/requireThrows.js

@@ -294,6 +294,26 @@ export default {
         },
       },
     },
+    {
+      code: `
+        /**
+         *
+         */
+        const itself = (b) => {
+          const a = () => {};
+          if (b) {
+            throw new Error('oops')
+          }
+          return a;
+        };
+      `,
+      errors: [
+        {
+          line: 2,
+          message: 'Missing JSDoc @throws declaration.',
+        },
+      ],
+    },
   ],
   valid: [
     {
@@ -362,5 +382,21 @@ export default {
         },
       ],
     },
+    {
+      code: `
+        /**
+         *
+         */
+        const itself = (n) => n;
+        `,
+    },
+    {
+      code: `
+      /**
+       * Not tracking on nested function
+       */
+      const itself = () => () => {throw new Error('oops');};
+      `,
+    },
   ],
 };