latte n:if and n:foreach on same div behaviour
- dkorpar
- Member | 135
For example
<ul>
<li>item</li>
<li n:if="!empty($rows)" n:foreach="$rows as $row">$row->id</li>
</ul>
will allways first run foreach. Which makes sense since then you can do:
<li n:if="$row->should_display" n:foreach="$rows as $row">$row->id</li>
but also is confusing developers…
I'm wondering would it be better to actually transform this in order which one
is written first? if or foreach?
so this would be different
<ul>
<li>item</li>
<li n:if="!empty($rows)" n:foreach="$rows as $row">$row->id</li>
</ul>
from
<ul>
<li>item</li>
<li n:foreach="$rows as $row" n:if="!empty($rows)">$row->id</li>
</ul>
But then again this is also maybe not the best idea…
Few other developers that work with me and me already bumped into this and not
really sure that this is solved in best way.
I'm not proposing anything just expect some disscussion :)
Last edited by dkorpar (2017-09-27 15:06)
- David Grudl
- Nette Core | 8205
This is intentional and the change would be a huge BC break, so it does not make sense to discuss about it :-)
For database queries is usually usable
<li n:foreach="$rows as $row">$row->id</li>
, when
$rows
can be null or false, you can use workaround
<li n:foreach="$rows ?: [] as $row">$row->id</li>
or <li n:foreach="(array) $rows as $row">$row->id</li>
- dakur
- Member | 493
I clash with this quite often, for example:
<div title="{$postFormat->name}" n:class="postsOverviewCarousel-item-image-postFormat, 'postsOverviewCarousel-item-image-postFormat-' . $postFormat->slug" n:foreach="$post->postFormats as $postFormat"></div>
$post
is an instance of Article
or
News
or StaticPage
which are DTOs with common parent
Post
. But each of these children may declare its own properties.
That's the case of postFormats
– some of them have it, some do
not. So $post->postFormats
can exist but does not have to. And
now n:if
with n:foreach
does not work for me.
@DavidGrudl As a new major version of Nette is in progress, when is better time to discuss it and make huge BCs then now?
Last edited by dakur (2017-10-06 10:36)
- David Grudl
- Nette Core | 8205
n:attributes are like HTML attributes: they occur only once, and the order does not matter.
- David Grudl
- Nette Core | 8205
I don't understand exactly what you would like to achieve and how one (@dkopar) or the second (@dakur) suggested solution would help you.
- dakur
- Member | 493
We use data containers in templates in our application which is kind of DTO/value object without getters and with public properties. Let's show two of them:
final class WorkshopDC extends PostDC
{
public $isWorkshop = TRUE;
public $id;
public $postFormats;
public function __construct(Workshop $workshop)
{
$this->id = $workshop->getId();
$taxonomies = $workshop->getTaxonomies();
$this->postFormats = TaxonomyUtils::convertTaxonomiesToDCs(Taxonomies::CATEGORY, $taxonomies); // Returns just an array of `TaxonomyTermDC` objects.
}
}
final class NewsDC extends PostDC
{
public $isNews = TRUE;
public $id;
public function __construct(News $news)
{
$this->id = $news->getId();
}
}
Then, in a template, we need to render a collection of these data containers
which are all children of abstract PostDC
.
public function renderOverview()
{
/** @var PostDC[] */
$this->template->posts = $this->wordpressFacade->getAllPosts();
}
So I would do this:
<div n:foreach="$posts as $post">
<div title="{$postFormat->name}" n:foreach="$post->postFormats as $postFormat" n:ifset="$post->postFormats"></div>
</div>
But it returns:
Undefined property: App\Presenters\DataContainers\PostTypes\NewsDC::$postFormats
rendering:
foreach ($post->postFormats as $postFormat) {
if (isset($post->postFormats)) {
// ...
}
}
But I would expect or like to render it in opposite order:
if (isset($post->postFormats)) {
foreach ($post->postFormats as $postFormat) {
// ...
}
}
Therefore, if interchangibility of n:foreach
and
n:if
is a feature (which makes sense to me as well), I suggest
n:outer-if
which would render the above. Now, as a
“workaround”, I have to use this:
<div n:foreach="$posts as $post">
{ifset $post->postFormats}
<div title="{$postFormat->name}" n:foreach="$post->postFormats as $postFormat"></div>
{/ifset}
</div>
@DavidGrudl Is it more clear now?
Last edited by dakur (2017-10-11 14:48)
- dakur
- Member | 493
P.S.: I'm not saying, that n:outer-*
attributes are good idea at
all as there will be three types of all keywords then which could be a bit
confusing, maybe. I just wanted to open a discussion about this problem I (we)
have, finding a solution or coming to an end, that this is the best we can do
with it.
Last edited by dakur (2017-10-11 14:52)
- David Grudl
- Nette Core | 8205
I see now. Just if/ifset
works for the cycle elements, not the
whole cycle. That it works this way was my decision, because I thought it is
more useful in practice.
Of course, a new macro like outerif
could be created, but
I feel it brings unnecessary complexity. Prefix outer-
is even
more problematic.
Solution with {ifset $post->postFormats}
is really good
enough. It seems even more readable to me.
If you like expressed way, this should work too
n:foreach="$post->postFormats ?? [] as $postFormat"