readFile JSON parse error includes filename

index.js

@@ -13,6 +13,7 @@ function readFile (file, options, callback) {
     try {
       obj = JSON.parse(data, options ? options.reviver : null)
     } catch (err2) {
+      err2.message = file + ': ' + err2.message
       return callback(err2)
     }
 
@@ -27,13 +28,15 @@ function readFileSync (file, options) {
   }
 
   var shouldThrow = 'throws' in options ? options.throws : true
+  var content = fs.readFileSync(file, options)
 
-  if (shouldThrow) { // i.e. throw on invalid JSON
-    return JSON.parse(fs.readFileSync(file, options), options.reviver)
-  } else {
-    try {
-      return JSON.parse(fs.readFileSync(file, options), options.reviver)
-    } catch (err) {
+  try {
+    return JSON.parse(content, options.reviver)
+  } catch (err) {
+    if (shouldThrow) {
+      err.message = file + ': ' + err.message
+      throw err
+    } else {
       return null
     }
   }

test/read-file-sync.test.js

@@ -34,6 +34,21 @@ describe('+ readFileSync()', function () {
     }
   })
 
+  describe('> when invalid JSON', function () {
+    it('should include the filename in the error', function () {
+      var file = path.join(TEST_DIR, 'somefile.json')
+      fs.writeFileSync(file, '{')
+
+      assert.throws(function () {
+        jf.readFileSync(file)
+      }, function (err) {
+        assert(err instanceof Error)
+        assert(err.message.match(file))
+        return true
+      })
+    })
+  })
+
   describe('> when invalid JSON and throws set to false', function () {
     it('should return null', function () {
       var file = path.join(TEST_DIR, 'somefile4-invalid.json')

test/read-file.test.js

@@ -33,6 +33,19 @@ describe('+ readFile()', function () {
     })
   })
 
+  describe('> when invalid JSON', function () {
+    it('should include the filename in the error', function (done) {
+      var file = path.join(TEST_DIR, 'somefile.json')
+      fs.writeFileSync(file, '{')
+
+      jf.readFile(file, function (err, obj2) {
+        assert(err instanceof Error)
+        assert(err.message.match(file))
+        done()
+      })
+    })
+  })
+
   describe('> when JSON reviver is set', function () {
     it('should transform the JSON', function (done) {
       var file = path.join(TEST_DIR, 'somefile.json')