Comments on: How to write a simple undo system for your app http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/?utm_source=rss&utm_medium=rss&utm_campaign=how-to-write-an-simple-undo-system-for-your-app helping you with javascript since 2007 Tue, 31 Jan 2012 11:22:00 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: dYcbbgcx http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-1408 dYcbbgcx Thu, 13 Oct 2011 14:12:03 +0000 http://www.javascriptkata.com/?p=188#comment-1408 <strong>2011...</strong> Hello, you used to write excellent, but the last several posts have been kinda boring… I miss your tremendous writings. Past several posts are just a little out of track! come on!... 2011…

Hello, you used to write excellent, but the last several posts have been kinda boring… I miss your tremendous writings. Past several posts are just a little out of track! come on!…

]]> By: Announcing the jsKata libraries » Javascript Kata http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-920 Announcing the jsKata libraries » Javascript Kata Tue, 15 Jun 2010 12:02:52 +0000 http://www.javascriptkata.com/?p=188#comment-920 [...] & redo I wrote about undo and undo & redo before. I took the code and put it in jsKata. You can look at the code or try [...] [...] & redo I wrote about undo and undo & redo before. I took the code and put it in jsKata. You can look at the code or try [...]

]]> By: An undo/redo library for your app » Javascript Kata http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-896 An undo/redo library for your app » Javascript Kata Mon, 26 Apr 2010 20:26:08 +0000 http://www.javascriptkata.com/?p=188#comment-896 [...] wrote about undo before and I pushed it farther. What about an undo/redo system? I extended the v.01 of the undo and [...] [...] wrote about undo before and I pushed it farther. What about an undo/redo system? I extended the v.01 of the undo and [...]

]]> By: Dan http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-883 Dan Mon, 05 Apr 2010 22:27:30 +0000 http://www.javascriptkata.com/?p=188#comment-883 @Joao You're right, the undo history is lost if you close navigate out of the page. In this case, this is not a problem but more a feature. I didn't talk about I consider it strong enough for an undo system because you probably don't want to navigate out of the page and then come back and have an undo history that is still filled. It would be confusing. But I agree that in certain cases, you might want one. Then, there must be plugins that exist to do that kind of thing. @Ryan Thanks a lot, improvements are coming in a new version. @Joao
You’re right, the undo history is lost if you close navigate out of the page. In this case, this is not a problem but more a feature. I didn’t talk about I consider it strong enough for an undo system because you probably don’t want to navigate out of the page and then come back and have an undo history that is still filled. It would be confusing. But I agree that in certain cases, you might want one. Then, there must be plugins that exist to do that kind of thing.

@Ryan
Thanks a lot, improvements are coming in a new version.

]]> By: Ryan http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-882 Ryan Mon, 05 Apr 2010 21:05:17 +0000 http://www.javascriptkata.com/?p=188#comment-882 Good methodology for handling this feature addition. Thanks for sharing! Good methodology for handling this feature addition. Thanks for sharing!

]]> By: João Pedro Pereira http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-881 João Pedro Pereira Mon, 05 Apr 2010 21:05:07 +0000 http://www.javascriptkata.com/?p=188#comment-881 I think that it may have a problem... Because it's client side you've a problem, if the user click on delete p.e. and then close the site the information won't be deleted. Right? I think that it may have a problem…
Because it’s client side you’ve a problem, if the user click on delete p.e. and then close the site the information won’t be deleted. Right?

]]> By: Dan http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-876 Dan Wed, 31 Mar 2010 14:42:03 +0000 http://www.javascriptkata.com/?p=188#comment-876 @Andrea I was already working with that idea and I talked about it on Reddit. @Charles Frank is right. You still have to write secure server code. And if someone is fool enough to do it, he will delete his own data. @Andrea
I was already working with that idea and I talked about it on Reddit.

@Charles
Frank is right. You still have to write secure server code. And if someone is fool enough to do it, he will delete his own data.

]]> By: Frank http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-875 Frank Wed, 31 Mar 2010 13:35:55 +0000 http://www.javascriptkata.com/?p=188#comment-875 Charles, This undo code is client-side only. You still have to write some secure code on the server :) Charles,

This undo code is client-side only. You still have to write some secure code on the server :)

]]> By: Charles http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-874 Charles Wed, 31 Mar 2010 11:21:03 +0000 http://www.javascriptkata.com/?p=188#comment-874 So what happens when client X looks at the code, and then decides to use some script to curl http://yoursite.com/users/delete?id=$n where $n goes from 0 to 10000? So what happens when client X looks at the code, and then decides to use some script to curl http://yoursite.com/users/delete?id=$n where $n goes from 0 to 10000?

]]> By: Andrea http://www.javascriptkata.com/2010/03/29/how-to-write-an-simple-undo-system-for-your-app/comment-page-1/#comment-873 Andrea Wed, 31 Mar 2010 10:12:08 +0000 http://www.javascriptkata.com/?p=188#comment-873 What you are trying to reproduce is the Command pattern. But you obtained only half of it. Instead of saving the "undo" function in an array, encapsulate both the "do" and "undo" functions in an object and pass this object to a function that - call the "do" - save the object in an array When you want to undo pick the object from the array (but leave it there) and call the "undo" If you want to redo pick the object from the array and call the "do" What you are trying to reproduce is the Command pattern. But you obtained only half of it.
Instead of saving the “undo” function in an array, encapsulate both the “do” and “undo” functions in an object and pass this object to a function that
- call the “do”
- save the object in an array
When you want to undo pick the object from the array (but leave it there) and call the “undo”
If you want to redo pick the object from the array and call the “do”

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