How to Embed a Collection of Forms

[trsteel88]

http://symfony.com/doc/current/cookbook/form/form_collections.html#allowing-new-tags-with-the-prototype

I noticed an issue with the above cookbook entry. It determines the index by counting the elements. However, this will cause issues when you are adding/deleting tags.

Eg, say you start with 3 entities in the collection. The fields would be outputted as

• tag[0][field]
• tag[1][field]
• tag[2][field]

Now, I delete the tag "1" with javascript. Result is:

• tag[0][field]
• tag[2][field]

Now, I add a new tag using js. Result will be:

• tag[0][field]
• tag[2][field]
• tag[2][field]

You will notice there are now 2 rows with the same index. How do people get around this. Should we be generating a random index instead of a length based index?

[merk]

In our bundle that provides a reusable javascript component for collections we initialise an internal count on creation of the page:

https://github.com/infinite-networks/InfiniteFormBundle/blob/master/Resources/public/js/collections.js#L41

Basically, we never reduce this count even if you remove a row, so in your final result it would be:

• tag[0][field]
• tag[2][field]
• tag[3][field]

[wouterj]

This is actually already fixed in the current code. For an explanation and the fix see #2158

I'm now going to close this, as the docs seems correct and then this better belongs to the mailing list/IRC/forum (since it's a general question about Symfony). If the docs are wrong, please comment again and I'll reopen + investigate it more :)