asked on

undo/redo array javascript

I'm working on a solution to make a custom undo/redo function in javascript.
Everytime an action occurs, the content of a div is added to an array.
Undo gives back the content before the last action etc etc.

Now the problem is that I want to make it about 10 steps or something, because otherwise the browser uses too mutch memory.
But I can't just throw away the beginning items of the array.

Can someone give me some hints in the right direction on how to solve this problem?

UnexplainedWays

Maybe a cycling array? I'm not to sure on the correct term.

(this would be done 1 @ a time, but just speeding it up.

[1][2][3][4][5][6][7][8][9][10]
^ index

You then add 3
[1][2][3][4][5][6][7][8][9][10]
^ index

You then add 5
[1][2][3][4][5][6][7][8][9][10]
^ index

Then you want and undo,
[1][2][3][4][5][6][7][8][9][10]
^ index

Then..
[1][2][3][4][5][6][7][8][9][10]
^ index
....
[1][2][3][4][5][6][7][8][9][10]
^ index

Now here's the trick, you now loop back to the begining.
[1][2][3][4][5][6][7][8][9][10]
^ index
..
[1][2][3][4][5][6][7][8][9][10]
^ index
And you want an undo now
[1][2][3][4][5][6][7][8][9][10]
^ index

And another undo
[1][2][3][4][5][6][7][8][9][10]
^ index
And another undo

[1][2][3][4][5][6][7][8][9][10]
^ index

UnexplainedWays

So as for code, you gonna need some if statments to catch all this,

like

undo()
{
index--;
if(index < 0)
index = 10;
}

redo()
{
index++;
if(index < 10)
index = 1;
}

UnexplainedWays

if(index < 1), my bad

ASKER CERTIFIED SOLUTION

0h4crying0utloud

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

SOLUTION

UnexplainedWays

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial