[RESOLVED] Array.reverse() is changing a constant!

[Endoplasmic]

Alright maybe I'm on the short-bus here, but I thought the whole purpose of a constant variable was so that it doesn't change.

Now I can work around the issue, but I thought it was important to note.

Steps to reproduce:

Create a constant array - public static const TEST_ARRAY:Array = new Array(1, 2, 3, 4, 5, 6);

Make a new variable that would be the array's reverse - var reverseArray:Array = TEST_ARRAY.reverse();

Trace the results - trace(TEST_ARRAY, reverseArray);

RESULTS:

6, 5, 4, 3, 2, 1
6, 5, 4, 3, 2, 1

Is this a bug or am I missing a better function to reverse the order of my array?

[neznein9]

Two things - first, when you store an array to a variable, you're not making a new array, just saving a reference. So in your example both TEST_ARRAY and reverseArray are the same object in memory.

Secondly, storing an object in a constant (eg. anything that's not a primitive or a literal) does not make it immutable. You can't put a new Array into that constant but you can modify the one that's there. On the same logic, you can put a bitmapData into a constant and still use the .draw() command - since it's the same bitmap, you're just altering the pixels.

[Endoplasmic]

Thanks for the reply, just sucks that reverse() is destructive instead of creating a new reference. I had to write some lame loop to re-write the array backwards which seemed pretty stupid. Oh well.

[neznein9]

You can use an empty .concat() to generate a copy of the first array:

const TEST_ARRAY:Array = [1, 2, 3, 4, 5, 6];
var reverseArray:Array = TEST_ARRAY.concat().reverse(); 

[wvxvw]

or slice() with no arguments (this will also create a copy of an array).

[Endoplasmic]

Thanks nez and wvx ( I ended up using the concat method ) that worked out great.