5 reasons why we are happy with AngularJS

I promised a general post about our experiences on sorted.jobs with AngularJS, so here's the view from ten thousand feet, rather than the 50 foot view of other posts.

1. Good for non-designers

In some ways this is more down to Bootstrap, but combine AngularJS, Bootstrap 3 and AngularUI you have a quick and easy way to produce a responsive and dynamic website.

2. Good for non programming web designers

Angular hides most of the Javascript so it makes for easy collaboration between a front end programmer and a designer. Angularjs directives mean that some of the clever bits can be presented to the designer as new HTML tags, which he can manipulate in the same way as other tags.

3. Very clear view seperation

Views live in templates, which are just HTML files, controllers  live in javascript controller files and never the twain shall meet. The actual controller function gets specified in an attribute to a <div> or other HTML tag -what could be easier (don't mention $scope)?

4. Decent documentation and community

The AngularJS site is pretty good, with a good tutorial, developer guide, and reference. Stackexchange is very active, Egghead.io is a good source of video tutorials although there are many others.  Manning has a couple of MEAP books; I have used AngularJS in Action, which is now nearly completed, the other is  AngularJS in Depth. Packt has a whole raft of AngularJS titles, I have used Mastering Web Application Development with AngularJS, I would guess the Manning books will be more up to date than the Packt one at the moment as they aren't formally published yet.

5. Testing tool.

Angular provides Protactor for end to end testing, this uses Selenium Webdriver to run Jasmine tests via standard web browsers. It is aware of Angular directives so you can run tests on Angular loops etc. It works well and the devlopers have been helpful when I found a problem.

That'll do for now, there's loads more and AngularJS has it's quirks, but I need coffee so that's another post.

Sorting and paging with AngularJS

We have two dashboard screens that make heavy use of AngularJS on sorted.jobs, one for candidates and one for recruiters. The recruiter screen in particular can end up with an awful lot of jobs on it, so the list needs to page, in addition it would be good to be able to sort by posting date, number of applicants, company name and so on.

Recruiter Dashboard

This is where we have got up to, not too happy about the UX/UI side, but it's workable. The paging is provided by the excellent AngularUI Booststrap library. Using it is pretty simple this is the AngularJS template directive ;

        <pagination total-items="active_jobs.total" ng-model="currentActivePage" ng-change="activePageChanged()"></pagination>

Pagination needs to know the size of the array it is paging over (active_jobs.total), has a variable to store the current page in (currentActivePage) and a function to call when you change the page - activePageChanged().

And here's the controller function :

  $scope.activePageChanged = function(i) {
    $scope.activePageStart = ($scope.currentActivePage -1) * $scope.itemsPerPage;
    $scope.activePageEnd = $scope.activePageStart + 10 ;
  }

As you can see all we are doing is changing the start end end points of the items we are viewing in the array; we have been a bit lazy and not passed itemsPerPage to the directive as we are using the default of ten.

The ng-repeat call looks like this :

      <div class='row' ng-repeat="job in active_jobs.hits.slice(activePageStart,activePageEnd)">

I did see pages offering a range filter but  array.slice() seems more direct.

In this example the whole array is passed from the backend to the front in one go (this is so it can be sorted in the browser), but you don't have to do it that way, other pages we have make a call to the back  end from within the activePageChanged() function  to get the next page of results.

Sorting

AngularJS provides the orderBy filter that will sort an array, the documentation is pretty good, the only real point to pick up is that to use it in our pagination example we need to call the controller version and not use the template filter version (this would only sort the array slice and not the whole array). So in the template we make a function call :

<p><a href="" ng-click="reverse=!reverse;active_order('_source.reference', reverse)">Reference<span class="glyphicon glyphicon-resize-vertical sort-col-header"></a></p>

We call the active order function with the column we want to sort by and the direction of sort. The  reverse=!reverse just twiddles the sort order.

We then need to set up the controller to use orderBy by injecting $filter :

function SomeCtrl ($scope, $location, $filter...

and using a bit of syntactic suger :

var orderBy = $filter('orderBy');

it is just a matter of defining the function :
           
  $scope.active_order = function(col, reverse) {
    $scope.active_jobs['hits'] = orderBy($scope.active_jobs['hits'], col, reverse);
  };        

and Robert is your father's brother.
 

AngularJS ng-if and ng-show

We use AngularJS to do a lot of the front end on sorted.jobs, at some point I may do some posts on the pros and cons of AngularJS, but for now it's enough to say that -in conjunction with Bootstrap it makes producing a front end pretty easy for a back end developer like me.

Anyhoo one of the joys of Angular is how easy it is to produce a display that varies depending on the data provided to it (even dynamically -although that's not the subject of this post). When we started sorted.jobs the way to do this was via ng-show and ng-hide, which basically twiddles the CSS display property for the element to show or hide it. This works very well, but the element would always be fetched from the server, it just wouldn't appear on the screen.

Now we have ng-if, this will remove the element from the DOM altogether if the expression evaluates to false, and so, assuming it is some some of resource it won't fetch it from the server, thus speeding up the page.

Quick Example

ng-show :
<img ng-show="job.user_id && !job.system.logo_url" ng-src="/logo/{{job.user_id}}/{{job_id}}" class="img-responsive">

ng-if :
<img ng-if="job.user_id && !job.system.logo_url" ng-src="/logo/{{job.user_id}}/{{job_id}}" class="img-responsive">

The ng-show in this case has a particularly bad effect in that it will load, although hide, an image that isn't there, i.e. one with no user_id!

References :

ng-if in Angular Docs
Stackexchange -you may want to read this if unexpected things start happening with ng-if, like some other Angular commands it has a habit of creating child scopes.

AngularJS, Google Search and SEO

Our new site sorted.jobs is now in a stealthy, pre-launch mode, so it is time to start thinking about getting it into the various search engines -especially the big one.

AJAX

Our Job Posts are normally served as AngularJS views -which Google can't parse, since they are AJAX based (although interestingly it can render them with Google Fetch) . However, Google can be persuaded to fetch another version of the page and index that by including this meta tag in the head :

<meta name="fragment" content="!">

If the crawler sees this tag it will then resend the original request with ?_escaped_fragment_= tacked on the end (more here : https://prerender.io/js-seo/angularjs-seo-get-your-site-indexed-and-to-the-top-of-the-search-results/)

so
http://www.sorted.jobs/job_post/UX+Developer/ULKYpZTSSRqBGvGirp_yOQ 
would become
http://www.sorted.jobs/job_post/UX+Developer/ULKYpZTSSRqBGvGirp_yOQ?_escaped_fragment_=

on the server side in the handler I recognise the second form and render a page that is HTML only.

SEO

Since the user doesn't see this page  it doesn't need the full functionality of the original  and we also have the chance to tweak the page to do things like providing a more meaningful <title> and a <meta name=description> tag which Google can do things with as per this snippet post

 Testing and Webmaster Tools

One minor 'gotcha' that we found was with Webmaster tools, in as much as the stats aren't up to date -according to tools we have 0 pages indexed wheres a site specific google search (site:sorted.jobs) shows us  the ten pages we expect.

A second issue is that the 'Fetch' functionality within Webmaster Tools doesn't fire off the second request automatically -so you can't see the page Google would actually index from sorted.jobs on the Fetch results page, just the originally requested AngularJS page.

On the plus side if you 'Fetch' the page you can check that the <meta name="fragment" content="!"> is in the content, and if it is you can then 'Submit to Index' which will kick off Google's crawler on your page and put it into their index within minutes.