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In response to @dcposch's feedback

index.js

@@ -231,6 +231,9 @@ function fromString (that, string, encoding) {
   var actual = that.write(string, encoding)
 
   if (actual !== length) {
+    // Writing a hex string, for example, that contains invalid characters will
+    // cause everything after the first invalid character to be ignored. (e.g.
+    // 'abxxcd' will be treated as 'ab')
     that = that.slice(0, actual)
   }