How to access an array in a JSON object?

That's because your base object is an array as well.

console.log(dataJS[0].comments[0]);

I suspect that would work

the JSON you have coming back is actually an array itself, so...

dataJS[0].comments[0].created_at

will be 2011-02-09T14:42:42-08:00, etc...

Both dataJS and comments are arrays, and need indexes to access the appropriate elements.

console.log(dataJS);
console.log(dataJS[0].eee1);
console.log(dataJS[0].comments[0]);

The object being returned is itself an array, so to get to the first comment (as an example), this is how you would access it:

dataJS[0].comments[0]