# Monday, 31 July 2017
Monday, 31 July 2017 11:40:00 (GMT Daylight Time, UTC+01:00)
# Friday, 24 February 2017

Last week, I delivered a presentation on Angular 2 and TypeScript at the Northwest Chicago JavaScript meetup. The organizers recorded my presentation, which you can watch here or below.

Friday, 24 February 2017 19:51:23 (GMT Standard Time, UTC+00:00)
# Saturday, 24 September 2016

At the Chicago Geekfest meetup last week, I delivered a presentation on AngularJS 2 and TypeScript. You can see the presentation below.

It’s worth watching just to hear Chris’s introduction at the beginning.

Saturday, 24 September 2016 15:53:03 (GMT Daylight Time, UTC+01:00)
# Monday, 01 August 2016
Monday, 01 August 2016 14:20:00 (GMT Daylight Time, UTC+01:00)
# Saturday, 26 March 2016

In the last article, we described the 2-way data binding with the ng-binding directive. In this article, I will introduce the ng-repeat directive.

Recall that a directive is a well-known attribute defined by AngularJS or your AngularJS application that is applied to an HTML element to provide some functionality.

The ng-repeat directive acts in a similar way to foreach loops or other constructs in a programming language. We point ng-repeat to an array of objects and Angular will loop through this array, repeating the HTML contained in the attributed element once for each element in the array.

In the following example, our controller creates an array of "customers" and adds it to the $scope directive, making the customers stateful and available to the HTML. Each customer has a firstName, lastName, and salary property.

var app = angular.module("myApp", []);
app.controller("mainController", function($scope) {
    $scope.customers = [{
      id: 1,
      firstName: "Bill",
      lastName: "Gates",
      salary: 200000
    }, {
      id: 2,
      firstName: "Satya",
      lastName: "Nadella",
      salary: 100000
    }, {
      id: 3,
      firstName: "Steve",
      lastName: "Balmer",
      salary: 300000
    }, {
      id: 4,
      firstName: "David",
      lastName: "Giard",
      salary: 1000000
    }];
}); 

In our HTML, we can loop through every customer in the array by applying the ng-repeat directive to a <tr> element, such as:

<tr ng-repeat="customer in customers"> 

Because the array contains 3 customers, the <tr> tag and all markup within this tag (including any bound data) will be repeated 3 times. As a result, the user will see 3 rows.

Here is the markup for the entire table.

<table>
  <thead>
    <tr>
      <th>First</th>
      <th>Last</th>
      <th>Salary</th>
    </tr>
  </thead>
  <tbody>
    <tr ng-repeat="customer in customers">
      <td>{{customer.firstName}}</td>
      <td>{{customer.lastName}}</td>
      <td style="text-align:right">{{customer.salary | currency:$USD}}</td>
    </tr>
  </tbody>
</table> 

The beauty of this is that we don't need to know in advance how many customers we have or how many rows we need. Angular figures it out for us.

The ng-repeat directive allows us the flexibility of repeating HTML markup for every element in an array.

Saturday, 26 March 2016 23:35:00 (GMT Standard Time, UTC+00:00)
# Friday, 25 March 2016

In the last article, we discussed Angular controllers. In this article, we will add code to a controller to do 2-way data binding.

The $scope object exists to hold stateful data. To use it, we add this object to the arguments of our controller, as shown in Listing 1.

app.controller("mainController", function($scope) {
...
} 

Because JavaScript is a dynamic language, we can create new properties on an object simply by assigning values to those properties. We can maintain state by adding properties to to the $scope object. For example, in Listing 2, we add the FirstName and LastName properties and assign the values "David" and "Giard", respectively.

app.controller("mainController", function($scope) {
  $scope.firstName = "David";
  $scope.lastName = "Giard"; 
}

Now that we have these values assigned, we can bind HTML elements to these properties in our web page, using the ng-bind attribute, as shown in Listing 3.

First: <input type="text" ng-model="firstName" />
<br /> 
 
Last: <input type="text" ng-model="lastName" /> 

We don't need to add the "$scope." prefix because it is implied. In this example, we bind these properties to 2 text boxes and the browser will display the property values.  But unlike the {{}} data binding syntax, this binding is 2-way. In other words, changing the values in the textbox will also change the value of the properties themselves. We can demonstrate this by adding a <div> element to the page to output the current value of these properties, as shown in Listing 3.

<div>Hello, {{$scope.FirstName}} {{$scope.LastName}}!</div> 

When the user modifies the text in the 2 textboxes, the text within the div immediately changes because both are bound to the same properties.

We can do the same with objects and their properties, as in the following example:

JavaScript:

$scope.customer = {
  firstName: "David",
  lastName: "Giard"
}; 

HTML:

First: <input type="text" ng-model="customer.firstName" />
<br /> 

        Last: <input type="text" ng-model="customer.lastName" />
By adding and manipulating properties of the $scope object and using the ng-model directive, we can implement 2-way data binding in our Angular applications.

Friday, 25 March 2016 10:26:00 (GMT Standard Time, UTC+00:00)
# Thursday, 24 March 2016

In the last article, I showed you how to set up your page to use Angular and do simple, one-way data binding.

In this article, I will describe modules and controllers.

A module is a container for the parts of an Angular application, including its controllers. This helps provide a separation of concerns, which helps us organize large, complex applications.

We create a controller in JavaScript with the following syntax:

app.controller("mainController", function() {
  ...
});

In the example above, we named the controller "mainController", but we can give it any name we want. The function argument contains the controller's code and we can pass into this function any Angular objects that we want the function to use.

One common parameter to pass to a controller function is $scope. $scope is a built-in object designed to hold stateful data. We can attach properties to $scope and they will be available in both the view (the web page) and the controller.

The ng-controller directive is an attribute that identifies which controller is available to a page or a section of a page. We can add this attribute to any element, but the controller is only available to that element and the objects contained inside it. If we add it to the body tag, it is available to anything within the body, as in the following example:

<body ng-controller="MyController"> 

which points to the MyController controller and makes it available to everything in the page body.

Once I do this, I can write JavaScript in this controller to add and update properties of the $scope object and those properties become available to the affected part of my page, as in the following example:

JavaScript:

var app = angular.module("myApp", []); 
 
app.controller("mainController", function($scope) {
  $scope.message = "Hello";
  $scope.customer = {
    firstName: "David",
    lastName: "Giard"
  }; 

HTML:

<body ng-controller="mainController">
  <h3>
    {{message}}, {{customer.firstName}} {{customer.lastName}}!
  </h3>
</body> 

In the above example, we use the one-way data binding to display the properties of $scope set within the controller. The output of this is:

Hello, David Giard

This is a simple example, but you can do what you want in a controller and anything created or manipulated in that function is availabe to your web page.

In this article, we introduced Angular controllers and showed how to use them in an Angular application.

Thursday, 24 March 2016 16:51:50 (GMT Standard Time, UTC+00:00)
# Wednesday, 23 March 2016
AngularJS is a popular framework that takes care of many common tasks, such as data binding, routing, and making Ajax calls, allowing developers to focus on the unique aspects of their application. Angular makes it much easier to maintain a large, complex single page application.

Angular is an open source project that you can use for free and contribute to (if you are skilled and ambitious).

As of this writing, AngularJS is on version 1.x. The Angular team is still actively working on the 1.x version; but they have already begun work on AngularJS 2.x, which is a complete rewrite of the Angular framework. AngularJS 2 is currently in beta and features some different paradigms than AngularJS 1. This series will initially focus on AngularJS 1, which has been out of beta for many months. In the future, after AngularJS is out of beta, I hope to write more about that version.

To get started with Angular 1, you need to add a reference to the Angular libraries.

You can either download the Angular files from http://angularjs.org or you can point your browser directly to the files on the Angular site. In either case, you need to add a reference to the Angular library, as in the examples shown below.

<script 
src="https://code.angularjs.org/1.5.0-rc.0/angular.js"></script> 

or

<script src="angular.js"></script> 

Angular uses directives to declaratively add functionality to a web page. A directive is an attribute defined by or within Angular that you add to the elements within your HTML page.

Each Angular page requires the ng-app directive, as in the examples below.

<html ng-app>

or

 
<html ng-app="MyApp"> 

The second example specifies a Controller, which is a JavaScript function that contains some code available to the entire page. We'll talk more about Controllers in a later article.

You can add this attribute to any element on your page, but Angular will only work for elements contained within the attributed element, so it generally makes sense to apply it near the top of the DOM (e.g., at the HTML or BODY tag). If I add ng-app to the HTML element, I will have Angular available throughout my page; however, if I add ng-app to a DIV element, Angular is only available to that DIV and to any elements contained within that DIV. Only one ng-app attribute is allowed per page and Angular will use the first one it finds, ignoring all others.

Once you have the SCRIPT reference and the ng-app attribute, you can begin using Angular. A simple use of Angular is one-way data binding. There are several ways to perform data binding in Angular. The simplest is with the {{}} markup. In an AngularJS application, anything within these double curly braces is interpreted as data binding. So, something like

The time is {{datetime.now()}} 

will output the current date and time. Below are a few other examples.

<h3>{{"Hello" + " world"}}</h3>
<div>{{5+2+3}}</div> 

which will output the following:

Hello World
10

If your controller contains variables, you can use those as well, such as:

<div>{x} + {y} = {x+y}! </div>

Although working with AngularJS can be complex, it only takes a small amount of code to get started.

You can see a live example of the concepts above at this link.

In this article, we introduced the Angular JavaScript framework; then, showed how to add it to your web application and perform simple, one-way data binding.

Wednesday, 23 March 2016 11:54:00 (GMT Standard Time, UTC+00:00)