This article is over a year old.
I am a bit ashamed to confess I do a lot of guessing in my work...
- You have to store the array length in advance before a loop? wtf?
- "for in" loops are inherently dangerous. wtf?
Every language has pitfalls but javascript seems king above even C++...
No. "for-in" loops that iterate through the properties of an object, and do something with them, without checking to ensure that the property is specific to that object, as opposed to something another library added to the Object.prototype, are dangerous.
The article did a poor job in that section of pointing out _what_ exactly is dangerous. It's not _every_ for-in loop. It's that one in particular, really.