What is the difference between facelets's ui:include and custom tag? - facelets

Ui:include and xhtml based tag (the one with source elt) seem to be much the same for me. Both allow to reuse piece of markup. But I believe there should be some reason for having each. Could somebody please briefly explain it? (I guess if I read full facelets tutorial I will learn it, but I have not time to do it now, so no links to lengthy docs please :)

They are quite similar. The difference is mainly syntactical.
After observing their usage for some time it seems the convention is that fragments that you use only in a single situation are candidates for ui:include, while fragments that you re-use more often and have a more independent semantic are candidates for a custom tag.
A single view might have a form with three sections; personal data, work history, preferences. If the page becomes unwieldy, you can divide it into smaller parts. Each of the 3 sections could be moved to their own Facelet file and will then be ui-include'ed into the original file.
On the other hand, you might have a specific way to display on image on many views in your application. Maybe you draw a line around it, have some text beneath it etc. Instead of repeating this over and over again you can abstract this to its own Facelet file again. Although you could ui:include it, most people seem to prefer to create a tag here, so you can use e.g. <my:image src="..." /> on your Facelets. This just looks nicer (more compact, more inline with other components).
In the Facelets version that's bundled with JSF 2.0, simple tags can be replaced by composite components. This is yet a third variant that on the first glance looks a lot like custom tags, but these things are technically different as they aren't merely an include but represent true components with declared attributes, ability to attach validators to, etc.


How many Stateless Widget Classes should a Flutter Developer put in one file?

I'm currently working on a flutter application. I have a file with a big widget tree. In order to easier understand, read and maintain I wanted to "crop" the widget tree.
First what I did was to create multiple functions, which represented a bigger part of the tree such as _createFancyImage() or _createFancyContainer. After some research, I found out that such a design has some downsides (see: https://github.com/flutter/flutter/issues/19269). So then I decided to create StatelessWidgets instead. Because of the huge size of the widget tree, I broke it down to 3 logical StatelessWidgets. Now I can use FancyImage() or FancyContainer() which represent each a standalone widget.
As a beginner, I'm not sure whether I should keep those StatelessWidgetclasses within the same file. Alternatively, I could create independent files. One thing to clarify: I'm not using those fancy widgets somewhere else. Those are unique to this one big widget tree otherwise I could have outsourced them into a new folder such as "common_widgets" or "components".
Unfortunately, I couldn't find something within the Dart and Flutter Repo style guides nor on the internet.
I appreciate every suggestion.
You can add as much classes as you need in a single file. It depends on the developer's mindset.
But, let say if one of your class can be reused by other classes or packages then you should add it to another file for better separation.
I can favour you one approach is that your each file should have maximum one Stateful widget and as many Stateless widgets as you want for that corresponding widget will be a better scenario.
Still in some cases if you feel that more than enough stateless widgets has been added in a single file you should separate it in another file based on your choice.
I prefer to keep one public widget which having the same name as the filename and remaining private widgets.
comming to your ques is How many widgets in a single file?
Its actually depend there is no such rule to restrict the limit of file. Different authors having different preference. I prefer try to keep 5-6 classes(widgets) and
each one having 5-6 functions.
Try to make a file single responsible i.e(5-6 classes together responsible for single functionality). Don't make god class which having unrelated concerns together later it will pains(haha)
If it's a common widget keep them separate to respect DRY principle(Don't repeat yourself)
If the widget is further divided into 3-4 widgets or it children widget change depend upon rest response keep seprate for good practise
Bonus Tip: try using code folding shortcuts to push a little more

Why do Visualforce pages require invalid HTML? (at times)

This has happened to me a couple times. Using something like an <img> tag, or <br>. Basically any HTML void element. Just today I attempted to use a <br>, and when saving got this:
Am I missing something?
Is there a reason for this?
Are void elements not intended for use in visualforce pages or components?
Or is this just flawed syntax checking?
Can be very frustrating at times, I ended up adding a false tag the other day because I realized it wouldn't be rendered and it was the only way to save my page...
P.S. I'm sorry if this has an easily accessible answer. I think I looked a reasonable amount, but not as much as usual before posting a question. Just couldn't even find search terms to get me close to something relevant.
Visualforce must be a valid XML document. Not HTML (which permits <img> without closing), not XHTML (because if you add any <apex:... tags not defined by W3C officially it's not a html document anymore, at least until it gets compiled and output becomes pure html0.
So you need <img> ... </img> or self-closing version, <img />.
In a way Lightning Web Components are even worse, self-closing doesn't work. Has to be explicit "end tag".
As to why... probably for easier ability to parse it as a valid document? I suspect they did it also for easier PDF generation.
This isn't exactly same topic but close enough I could find in reasonable time: https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/pages_styling_doctype.htm

Angular directives - element or attribute?

I'm part of a team with about 6 UI devs, of varying quality and next to no Angular experience. Many are contractors, with little experience with the code base. The app has a very fancy (complicated) UI. It supports IE8+ (soon hopefully IE9+).
We're introducing Angular for a major extension to the app, and I've been asked to write guidelines on the use of Angular for the team.
We'll use directives to create fancy UI elements, all prefixed with "ipwr" to avoid name clashes. I'm trying to decide whether to mandate that devs give their directives the restriction "element" or "attribute". Mandating only one, to avoid chaos and confusion.
My question is: what restrict is better or more popular for directives, "element" or "attribute"?
My main concern is ease of use for people with little Angular experience who are new to the application code base, to reduce bugs, copy and paste behaviour, etc.
The angular guidance says that you should use the "element" restriction whenever the directive has full control over it's template meaning it has a template that it is rendering out, etc.
For attributes, they suggest to use these only when you are adding "behavior" to an existing element or decorating an existing element.
For example, think of the ng-click directive, this is used a attribute not as a element because the click directive is just adding the click behavior to some element.
Another example would be the ng-repeat directive, it is also used as an attribute not as a element because it is going to repeat the element in which it is being used in.
Now, this guidance is from the angular documentation; however, I don't know necessarily that element vs. attribute is going to give you a "better" approach it's more of a convention.
Now if you have to support older browsers, then you may want to consider using either the comment or class directives.
My personal preference is to just use the attribute restriction; mainly because people that are new to angular get overwhelmed at first when they see the restrict and it's variations of the options that can be used.
I usually defer to the John Papa AngularJS style guide when making these types of decisions. He says:
Lean towards implementing as an element when its standalone and as an
attribute when it enhances its existing DOM element.
If you want to keep your HTML valid you'd use attributes, e.g. if you have a directive ipwr-modal, you can declare it as <div data-ipwr-modal="you-could-put-some-binding-here"></div>.
When creating directives with a custom layout, however, you'd better use element declaration (if you don't need to have your HTML valid). This is the more obvious way to say: "hey, we have a custom component here".
This blog post explains it with some more ideas
Some points to consider:
Most of the time attributes is the best/most convenient option (it's not the default by chance).
Anything you can do with element-bound directives, you can do with attribute-bound as well.
Element-bound directives can be more descriptive/readable at times.
If you want your code to pass certain types of validation, you should use attributes.
Since you want to support IE8, keep in mind that custom tags have an extra overhead (more info), which hurts maintainability.
BTW, you can't limit directives to elements only (without affecting functionality), so it is more a question of allowing 'element' or not. Note that an element often has more than one directives and directives placed on the same element can cooperate and augment each other's behaviour. So limiting the use of directives to 'element', means limiting the number of custom directives per element to 1, which severly reduces the functionality-potential.
That said, this is what I ('d) do:
If IE8 is not an issue, allow both (mostly use attributes).
If IE8 (or the overhead for custom tags) is an issue, use only attributes.
In general, if only one form should be allowed, it should be attributes (works anywhere, no extra overhead, offers all functionality).

how can I exclude an element from an Angular scope?

my premise was wrong. while AngularJS was certainly slowing things down, it was not due to the problem I describe below. however, it was flim's answer to my question - how to exclude an element from an Angular scope - that was able to prove this.
I'm building a site that generates graphs using d3+Raphael from AJAX-fetched data. this results in a LOT of SVG or VML elements in the DOM, depending on what type of chart the user chooses to render (pie has few, line and stacked bar have many, for example).
I'm running into a problem where entering text into text fields controlled by AngularJS brings Firefox to a crawl. I type a few characters, then wait 2-3 seconds for them to suddenly appear, then type a few more, etc. (Chrome seems to handle this a bit better.)
when there is no graph on the page (the user has not provided enough data for one to be generated), editing the contents of these text fields is fine. I assume AngularJS is having trouble when it tries to update the DOM and there's hundreds SVG or VML elements it has to look through.
the graph, however, contains nothing that AngularJS need worry itself with. (there are, however, UI elements both before and after the graph that it DOES need to pay attention to.)
I can think of two solutions:
put the graph's DIV outside the AngularJS controller, and use CSS to position it where it's actually wanted
tell AngularJS - somehow - to nevermind the graph's DIV; to skip it over when keeping the view and model in-sync
the second option seems preferable to me, since it keeps the document layout sane/semantic. is there any way to do this? (or some, even-better solution I have not thought of?)
Have you tried ng-non-bindable? http://docs.angularjs.org/api/ng.directive:ngNonBindable
<ANY ng-non-bindable>

What kinds of things can be done to improve the tagging functionality on a website?

I have rough ideas - like dealing with singular/plural, two or more words/phrases that mean the same thing, misspellings, etc. But I'm not sure of any patterns or rules of thumb for dealing with these, either programatically and automatically or by presenting them to administrators or even users to clean up.
Any thoughts or suggestions?
You should have a policy for the format of the tags (e.g. tags should be singular). Depending on how diverse the tags are, it might be useful not only to auto-complete while you are typing in a tag, but also to suggest similar tags, so that it is easy for people to use the tag system. Additionally, a cleanup process could correct common spelling mistakes and substitue deprecated tags according to a translation table.
As SO does, suggesting existing tags as you type is a very good thing.
It will (hopefully, almost) take care of the plural / singular thing and misspellings, as people will re-use existing tags much more.
Use an ajax-driven suggestion form, like StackOverflow :)
Assuming a setup not dissimiliar to SO: how about moderators being allowed to merge a smaller voted tag into a more common one, e.g. VS9 could be merged into VisualStudio2008 but not letting the larger used tag to be merged into a smaller tag grouping. Adding a badge incentive or similiar to this.