#if _collection.any? around #each causes duplicate first item

[derikson]

{#if _collection.any?}{#each _collection as c}{c.name}{/}{/} will cause the first item to be output twice, once at the beginning and once at the end. The same thing happens with .empty?, but does not happen with .size == 0.

You can test this by editing app/main/views/blog/edit.html in the todos3 app and wrapping the {#each _posts as post}{/} block with a {#if _posts.any?}{/} conditional.

[ryanstout]

Thanks for the heads up. I think I know why this might be happening. I'll try and get it fixed tomorrow.

[derikson]

Forgot one major detail. The bug doesn't occur right away. You have to reload the page for it to trigger.

[derikson]

Check https://github.com/derikson/todos3/tree/topic/issue-36 for a demonstration of this bug. That's branch topic/issue-36, not master.

Go to blogs, enter a blog, then reload the page using the reload button in your browser. You should see a duplicate of the blog entry.

[derikson]

I noticed {#if _posts.size > 0} and {#if _posts.length > 0} don't trigger the bug, while {#if _posts.count > 0} does. ReactiveArray has an implementation for #count, but relies on method_missing for the other two. Maybe that's just a coincidence, though.

[derikson]

Removing the #count method in ReactiveArray doesn't change anything, so it's just a coincidence.

[derikson]

Stepping over the javascript, I found that the call to #reload in EachBinding#initialize creates the extra element when the bug is triggered.

[ryanstout]

@derikson Thanks. I'm pretty sure the new reactive will fix this issue. Should be out early next week.

[ryanstout]

@derikson Can you use volt 0.8 and see if you can duplicate this? (You might have to do a new app) I wasn't able to duplicate. Closing for now. Feel free to re-open.

[derikson]

It can't replicate the bug anymore. Confirmed fixed.

[ryanstout]

Thanks