I am working on something like CMS based on AngularJS templates. I need to get bindings from a template so my users are able to fullfill those properties for specific pages.
So how can I get all bindings from a template?
You can't... using techniques AngularJS itself provides. Your question is just beyond the scope of the functionality the core devs thought to provide.
#bmceldowney is correct - a regex could be used to parse templates, although I think that would be challenging for a few reasons:
AngularJS templates can contain all sorts of complex expressions, not just simple vars. How will you deal with filters - and if you won't, you lose a lot of value here...
AngularJS can lazy-load templates and this is a common practice. You wouldn't want hundreds of useless templates floating around just in case they might be used at some point. How will you deal with templates that haven't been loaded yet - that you don't know exist?
If you're building a CMS that implies data management of some kind, and that's not going to get stored in the front-end because it would be useless there - nobody else would ever see it. So aside from the editing cycle itself, it seems like something to be solved server-side and not with AngularJS.
All that said, my suggestion would be to do exactly that - work out something server-side where you can access templates as raw files just by scanning some folder where they're stored, use regular expressions to find the template variables, and you're going to have to be clever with how you parse expressions and what you'll support here. Then you can prepare appropriate data objects to pass down to the client via an API for it to support the actual editing.
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Simple enough question I think. I see people raving about it but I haven't seen anything on the "why" use it. It doesn't seem to me (from my naïve outside perspective) ng-repeat, if not in that nested layer do ng-repeat inside another. I looks like that it doesn't add functionality that angular doesn't already have—I'm sure I'm wrong—
I see the term "lazy loading" being used with it and it doesn't seem like it's that much easier after seeing there docs. What are some things lodash makes significantly easier in AngularJS specifically that I would make it work adding another lib to my project? And what can you do with it that you cannot with angular out of the box?
They're just not the same, and exist for distinct reasons. I think you already know what AngularJS works for, so about your questions:
What can you do with it that you cannot with angular out of the box?
Well, if you need to deal with several data in structures like arrays, objects or mixed/nested shapes, lodash will save you a lot of time and effort.
Maybe there's a lot of items in collections which should be presented to your client application in some particular way, you would have to write a lot of JS code in Angular controllers or services with out the aid of lodash.
If there's a lot of logic tied to your data structures and/or complex algorithms and coding workflow, go for lodash.
Lodash is a great tool, you can get some intro here and of course, just check out the API reference. You can use it at everywhere, either Angular or any other framework, and of course, also at Node too!
I have seen many people using handlebars templates with BackboneJS instead of underscore templates, even underscore is hard dependency of BackboneJS. Can anyone please tell me benefits of doing so?
Handlebars:
Compatible with mustache templates - what cam be used to use same syntax, or even templates
More readable syntax
Underscore:
No need to load extra library for template
Underscore its not only template engine. It has 80+ useful functions for working with objects, arrays and collections.
On my point of view there are a lot of advantages and disadvantages of using these libs according project specifics.
It depends on where you are using and what you are needing a template for.
For example, like Evgeniy said, when you want to deal much with collections, such as SORT, or extracting a particular field's value (from a result set), extracting UNIQUE values ... these are the places where you will be better off using Underscore.
Going back to what Evgeniy said, I think it is those 80+ useful functions that make Underscore significant.
I prefer Handlebars for Templates, because I feel that handlebars is more readable and a bit less complex than Underscore when it comes to Template needs. Again, that's my preference.
But bottom-line is, I user Underscore for the Functions it provides and Handlebars for Templates.
Hope this helps.
Underscore provides the basic functions needed for any project and thats the advantage of that.
At the same time Handlebars can be efficiently used in a project which needs to do lot of formatting/ common functions with some set of data. For e.g. if a project has requirement of displaying a name in a specific format and has to be in sync across the application, then handlebars come in handy.
We can simply write a handlebar and call that function from all the places in the application.
In short i would say both are handy for development and they are wonderful in their own ways.
Hope i have not confused you :)
I have been searching online and have not been able to come across an example. Does anyone know of any resources for using nested attributes with AngularJS?
There's a lot of good information here and I've found it pleasant to work with. Their library does a lot of wiring for you, and I'm just starting to play with nesting the attributes but I did read on a blog that this library does it. I'll post more as I know it.
https://github.com/FineLinePrototyping/angularjs-rails-resource
Alright just did some quick reading on Nested Attributes in Rails here: http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html
As far as I know there's no such equivalent provided with Angular. Generally speaking angular works with JSON encoded data coming back from requests like
{
"id":1,
"name":"Shaun"
}
and otherwise data is stored with Plain old javascript objects (or specific object types if a developer so chooses to create them).
There's lots of good info on various ways to use JavaScript on Crockford's site here http://www.crockford.com/javascript/javascript.html
But so far as I know you'll have to roll your own solution. I did a bit of googling on Nested Attributes and javascript and mostly the solutions/topic seem focused around Backbone.js but you might be able to adopt the same concept and just replace Backbone.js methods with their angular equivalents.
As it stands today angular doesn't really do a whole lot when it comes to your model outside of watching for property changes and updating things during a digest. My understanding is working on better functions for the models is a large part of what's in the works for version 2.0 whenever that hits.
I'm using AngularJS 1.0.8.
The problem: I have a dynamic website that can be built from various components, or widgets: paragraphs, text blocks, images, hyperlinks, and tables, for that matter.
A paragraph is a container of more components. A table is also a kind of a container - it can hold other components, and it arranges them as a datagrid.
The website is not static, i.e. I don't have a pre-defined layout of such components.
Instead, I get a JSON in startup, that specifies the layout of the components.
Originally, I had a directive of each such component, using templates for that directives, and occasionally using $compile to change the DOM a bit for more complex components.
For the 'container' components - paragraphs and tables - I used ngRepeat to render all of the components that are contained in that container-component.
That was problematic performance-wise. It would take the website many seconds to load on Chrome/Firefox, with the time spent mainly in the AngularJS render mechanism (not in IO, I figured).
So I decided to change the directives of these components. Instead of using ngRepeat, which is not really necessary since I don't need the two-way binding (the content in the website is not interactive and cannot be changed, so really I only need to render it once, very much like a servlet) - I built the HTML string in the directive myself, using plain JS, iterating over all of the contained components that exist in the model, and at the end I $compiled and linked it.
The result wasn't good enough again.
For a table of a few hundered cells, it took ~500 milis to link in modern Chrome/Firefox, and ~4000 milis in IE9, and ~15000 milis in IE8, and IE7 is still rendering so I can't give you the time :)
I thought that the problem might be with an extensive use of directives.
A simple:
<div my-table-component data="data"></div>
element would result, after the link, in a <table> tag with 30-40 <tr> tags, each with 10 <td> tags, and in each there would be an additional <div my-text-component> or <div my-image-component> that would then have to be compiled and linked by itself (since it has a directive).
I though that since my website is not interactive to begin with, I don't really need this.
Maybe I could avoid using directives for each component, and leave only a directive for the container-components. In these directives, I would create the actual HTML template of every possible other component, instead of using directives that would do that.
That takes me another step away from the AngularJS idea towards a servlet idea. And it kind of sucks.
So maybe one of you can offer a better approach for me... Maybe the performance problem is not even there? Maybe a use of directives (and hopefully ngRepeat) can be fine performance-wise even with this amount of items? Maybe there's a better way to make an insightful performance benchmark, other than using Chrome's Developer Tools, Firebug, and Chrome's Batarang AngularJS extension (none of them really directed me in a productive way).
Using a lot of nested directives by itself is not a problem, but any extensive binding could have huge impacts.
If someone is still looking for an aswer to this, using Angular 1.3+, OP could solve his problem by first using one-time binding on all the elements on which he says there is "no need for two-ways bindings", using the ::binding syntax.
In addition, I would suggest trying to spot which bindings exactly are being particularly slow, using the amazing profiling snippets from this website: http://bahmutov.calepin.co/improving-angular-web-app-performance-example.html
Finally, what often takes most time in Angular, especially while building big ng-repeated tables, is the compilation phase. So if possible try to only build a restricted number of elements (using limitTo) and then load more as the user scrolls for instance. Many directives address this concern (look for "infinite scrolling")
All in all, I think it is still worth trying to optimize an Angular application rather tham switching to native JS, most of the time the lag comes from a developper mistake: some applications have thousands of watchers and run pretty smoothly (*cough* like mine *cough*).
I just started to learn AngularJS and struggle with some concepts of AngularJS. It would be great if somebody could explain me some points...
I understand that ng-click is technically not the same as onclick (see here), but both are placed in the markup. I thought that would be a "bad practice"? Why is this one of the core concepts of AngularJS, if most people say this is "bad"? I thought it would be better to select the DOM element from JavaScript and not to place logic in the markup.
If ng-click is the right way to react to click events in AngularJS what should I do with other DOM events? I see that there are several other directives like ng-mouseover, but not all DOM events have a AngularJS equivalent. How would I handle a 'drop' event in AngularJS (hence in the AngularJS way - not the normal way)? To be clear: I want to drag a file into my webapp.
Thank you very much,
Pipo
Why is this one of the core concepts of AngularJS, if most people say this is "bad"?
Well, people who really like Unobtrusive JavaScript might say it is bad. Angularians (and those with a flex background) see value in the more declarative approach.
"Angular is built around the belief that declarative code is better than imperative when it comes to building UIs and wiring software components together... By declaratively describing how the UI should change as your application state changes, you are freed from low level DOM manipulation tasks. -- Overview doc
See also Don't the data attribute options used in Bootstrap, Angular.js, and Ember.js conflict with Unobtrusive Javascript principles?
what should I do with other DOM events?
Write your own directives to listen for them (or find one that someone else has already written). Angular gives you the power to extend what the browser can do -- by writing your own directives.
Update: in the comments below, Tim Stewart mentions AngularUI's ui-event, which lets you bind a callback to any event not natively supported by Angular.
By nature, Angular requires elements in the markup in order to function properly. Further, those elements must be "compiled" each time they change, for the most part. So, it's already somewhat "obtrusive" irrespective of the JavaScript. You can't simply replace the markup, and have everything auto-bound for you like you can with something like jQuery.
Strictly speaking, unobtrusive JavaScript:
1. separates structure and behavior, in order to make your code cleaner and script maintenance easier
2. preempts browser incompatibilities
3. works with a clean, semantic HTML layer
(Wikipedia)
That's not Angular, for sure. In order to achieve the two-way binding on everything, they chose to make custom binding points in the DOM, as opposed to using a class name or ID the way that jQuery would do. (A somewhat non-standard approach, but it obviously works.)
But the real way to think of it is this: Basically each controlled section of your markup is not really straight HTML anymore anyway. It's really more of a template now, and as such requires interaction with the engine that is preparing it for rendering. As such, the traditional rules of unobtrusiveness don't really apply... (FWIW, I'm a huge fan/user of the jQuery.on() function to bind elements to events automatically when the element is added to the page. Very clean and flexible, IMHO, and I do wish there was a similar mechanism in Angular. I like adding a class to items in multiple locations on the page that invoke the same event handler automatically. Having a single place to go change code is a good thing. but I digress...)
For me, the bigger issue is that of progressive design. Does the web page work without JavaScript enabled at all? Does anyone really care about that? Hmmm...