Question

Consider, I have this object:

var ob = {
  "page1.html" : {...},
  "page2.html" : {...},
  "page3.html" : {...}
}

I am unable to change this to an array, I don’t have access to that, what I’d like to know is if it is safe to access the object properties by index, so:

var obVal = ob[0]; // reliably returns "page1.html"'s value every time

I know that a for each loop shouldn’t be used in this situation because the values are hashed or something? But reference by index might be ok?

Answer 1

No, ob[0] won’t even work – it will give undefined. In fact if your object was:

var ob = {
  "0": "blah",
  "page1.html" : {...},
  "page2.html" : {...},
  "page3.html" : {...}
}

ob[0] will give you "blah".

A for-each loop is the right tool for this situation, but you should just check that each index in the loop actually belongs to the object, and not to a parent:

for (var i in ob) { // i will be "page1.html", "page2.html", etc...
    if (!ob.hasOwnProperty(i)) continue;
    // Do something with ob[i]
}