fs: move type checking on fs.fstat to js

PR-URL: #17334
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Author: jasnell

lib/fs.js

@@ -981,7 +981,7 @@ fs.readdirSync = function(path, options) {
 };
 
 fs.fstat = function(fd, callback) {
-  if (typeof fd !== 'number')
+  if (!Number.isInteger(fd))
     throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'fd', 'number');
   if (fd < 0 || fd > 0xFFFFFFFF)
     throw new errors.RangeError('ERR_OUT_OF_RANGE', 'fd');
@@ -1011,7 +1011,7 @@ fs.stat = function(path, callback) {
 };
 
 fs.fstatSync = function(fd) {
-  if (typeof fd !== 'number')
+  if (!Number.isInteger(fd))
     throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'fd', 'number');
   if (fd < 0 || fd > 0xFFFFFFFF)
     throw new errors.RangeError('ERR_OUT_OF_RANGE', 'fd');

src/node_file.cc

@@ -634,10 +634,7 @@ static void LStat(const FunctionCallbackInfo<Value>& args) {
 static void FStat(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
-  if (args.Length() < 1)
-    return TYPE_ERROR("fd is required");
-  if (!args[0]->IsInt32())
-    return TYPE_ERROR("fd must be a file descriptor");
+  CHECK(args[0]->IsInt32());
 
   int fd = args[0]->Int32Value();
 

test/parallel/test-fs-stat.js

@@ -130,3 +130,41 @@ fs.stat(__filename, common.mustCall(function(err, s) {
     assert.strictEqual(typeof parsed[k], 'string', `${k} should be a string`);
   });
 }));
+
+['', false, null, undefined, {}, []].forEach((i) => {
+  common.expectsError(
+    () => fs.fstat(i),
+    {
+      code: 'ERR_INVALID_ARG_TYPE',
+      type: TypeError,
+      message: 'The "fd" argument must be of type number'
+    }
+  );
+  common.expectsError(
+    () => fs.fstatSync(i),
+    {
+      code: 'ERR_INVALID_ARG_TYPE',
+      type: TypeError,
+      message: 'The "fd" argument must be of type number'
+    }
+  );
+});
+
+[-1, 0xFFFFFFFF + 1].forEach((i) => {
+  common.expectsError(
+    () => fs.fstat(i),
+    {
+      code: 'ERR_OUT_OF_RANGE',
+      type: RangeError,
+      message: 'The "fd" argument is out of range'
+    }
+  );
+  common.expectsError(
+    () => fs.fstatSync(i),
+    {
+      code: 'ERR_OUT_OF_RANGE',
+      type: RangeError,
+      message: 'The "fd" argument is out of range'
+    }
+  );
+});