Things That Work

…says Chris of Grooveshark’s rather disappointing entry for the “Bug of the Beast”:

So one of my bug reports this week was that Lite took an insanely long time to populate the list of playlists when you clicked the “Add to Playlist” button on a song’s info panel. We’re talking like, click the button, lightbox opens, 4-5 seconds later your playlists appear. This was happening even for accounts with a small number of playlists.

At first I thought it must be something with the service call to the backend to fetch the list of playlists, but it was returning long before the list rendered.

So then I thought perhaps it was the class I wrote for paging lists of stuff from the backend, but no, parsing the data wasn’t taking that long either.

So I went to make sure I hadn’t done anything silly in the view, like, manually removed and replaced all the children in the box every time the list changed instead of just using a Repeater. But no, I was using a Repeater. Jay says, “What’s this recycleChildren property on the Repeater class?”

I said, “That shouldn’t matter, this is the first time that Repeater’s been rendered. There’s no children created yet *to* recycle. But I guess I’ll set it true anyway.”

And sure enough, now it renders in more like 1 second, as opposed to 4-5. I understand how recycleChildren increases performance when the data in the dataProvider changes. I think it’s silly that it defaults to false – I’d think that most common uses of the Repeater class would benefit from defaulting to true, and if you have a case where you need it false, then you can specify. But I still don’t understand how it’s faster when it’s the first time it’s created any children at all.

So if your Repeaters are slow – set recycleChildren to true!

And if anyone can give some insight into how it’s faster even on the initial creation of the component, let me know. I’m curious.

And for you Grooveshark Lite fans – that change is live, so if you were frustrated by long lag times on the “Add to Playlist” lightbox, the “Share” lightbox, or on opening a playlist or song info panel, it should be much better now.