MVC In Angular

Definition Recap

  • Model: How we model our data in the code
     
  • View: What the user sees
     
  • Controller: How the model and the view communicate

Model, in Angular

  • The model still represents the state of the program and the important data.

     
  • Angular lets us model data in plain old JSON objects
     
  • Angular GIVES us "Services" and "Factories" which are helpful data modeling tools

Model, in Angular

  • Persistence has to be managed through AJAX, since we're trying to avoid nasty "page loads".

     
  • All model code in Angular is client side JS code, but there may be a corresponding database model. Probably exposed by an API.

View, in Angular

  • The view, in Angular, is still represented by HTML.
  • Custom directives, and a special templating syntax are used.
  • Render data: {{ exaluatedJavaScript }}
  • 2-Way data binding:
    <input ng-model="variableName" >
     

Controller, in Angular

  • Built with a specific Angular component, called a "controller"

     
  • Behavior is defined in JavaScript

     
  • Views must declare their controller in HTML using a custom attribute
     

Controller, in Angular

// JavaScript Controller Definition

// Application name, followed by an array of dependencies
// dependencies are similar to 'require' statements
var application = angular.module("myapp", [])

// Register a controller on our application
// Name, followed by the code for instantiating the controller
application.controller("HelloController", function($scope) {
    // $scope is VERY special. We'll get to that. 
    $scope.hello = {};
    $scope.hello.title = "World";
  });

Controller, in Angular

<!-- Declare the application that this view belongs to -->
<html ng-app="myapp">
  <head>
    <meta charset="utf-8">
    <title>Hello, World!</title>
  </head>
  <body>
    <!-- declare the controller this div (and it's children) belongs to -->
    <div ng-controller="HelloController">
      <!-- hello.title here, is tied to $scope.hello.title -->
      <h2>Hello, {{hello.title}}!</h2>
    </div>
  </body>
</html>

$scope: "View Model"

  • All communication between the view and the controller is managed by the $scope variable.
     
  • If you want something to be used by the view, you have to put it on the "view model", which in Angular is the $scope variable.
     

A Mental Model

View

HTML

Controller

JS, specifically constructed in a

.controller function

$scope

User input flows from

the view to the ctrl

Data from the program flows from the ctrl to the view

Questions?

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