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Created January 13, 2015 23:11
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This exaplains how we can take advantage of factories to share data across controllers in angular.js source http://jsbin.com/feciqatari
Raw
index.html
<!doctype html>
<html ng-app="myApp">
<head>
<meta name="description" content="This is a template for angular experiments" />
<script src="http://code.jquery.com/jquery-2.1.0.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.0/angular.min.js"></script>
</head>
<script src="http://angular-ui.github.io/ui-router/release/angular-ui-router.min.js"></script>
<body>
<ul>
<li>
<a href="#factories">Understanding Factories</a>
</li>
<li>
<a href="#sharing-data-on-controllers">Sharing data between controllerss</a>
</li>
<li>
<a href="#topic1">Javascript: Objects passed as reference</a>
</li>
<li>
<a href="#topic2">When does the reference stop working?</a>
</li>
<li>
<a href="#example">Example</a>
</li>
</ul>
<h1 id="factories">Understanding Factories</h1>
<h2 id="sharing-data-on-controllers">Sharing data between controllers</h2>
<span><b>by marcio reis</b></span>
<h5 id="topic1">Javascript: Objects passed as reference</h5>
<p>
Any singleton is passed as reference when it comes to javascript.
</p>
<pre>
var b = { name: 'Ricardo' }
var a = b;
//updating the property name of b.name to something else will cause the a.b to be updated. This is what happens when when we use factories.
</pre>
<h5 id="topic2">When does the reference stop working?</h5>
<p>Whenever we try to bind an object to other object properties the reference is lost and changing values wont be reflected anymore without our intervention</p>
<pre>
var b = { name: 'Ricardo' }
var a = b;
var c = b.name; //c is now 'Ricardo';
c = 'Maria';
// b.name is still Ricardo
// a.name is still Ricardo
</pre>
<!--
THE DEMO
-->
<div id="example" style="background:#f3f3f3">
<h1>Example</h1>
<h4>Keep data sync using the object reference <a href="#topic1">from here</a></h4>
<div ng-controller="foo">
This controller updates the property when we click the link 'update' <br/>
{{binValue.getByte();}}
<input type="text" ng-model="value">
<a href="javascript:void(0);" ng-click="setBin()">update</a>
<span style="color:red;">The input value doesn't update when you write on the inputbox of the second example because it's a different property! </span>
</div>
<br/><br/>
<div ng-controller="bar">
This controller has a two-way binding input between the input value and binFactory property 'byte' which causes other scopes that are bound to the same object reference to update automatically <br/>
{{binValue.getByte();}}
<input type="text" ng-model="binValue.byte">
</div>
<br/><br/>
<h4>Failing Examples</h4>
<div ng-controller="fooFail">
{{binValue.getByte();}}
<input type="text" ng-model="value">
<a href="javascript:void(0);" ng-click="setBin(value)">update</a>
<span style="color:red;">DON'T!!! This example binds the scope to different properties and methods of our factory. This breaks the object reference!</span>
</div>
<br/><br/>
<div ng-controller="barFail">
{{binValue.getByte();}}
<input type="text" ng-model="value">
<a href="javascript:void(0);" ng-click="setBin()">update</a>
<span style="color:red;">DON'T: This example doesn't update when we change the value on the first 2 examples because it's bound to a property of the factory. ($scope.value = 'binFactory.byte'). But when we click the update button the first to examples are updated because we call the method setByte on it's own object reference</span>
</div>
</div>
<script id="jsbin-javascript">
angular.module('myApp',[])
.controller('foo', function(binFactory,$scope){
$scope.binValue = binFactory;
$scope.setBin = setBin;
$scope.value = 'foo';
function setBin(){
binFactory.setByte($scope.value)
}
})
.controller('bar', function(binFactory,$scope){
$scope.binValue = binFactory;
})
.factory('binFactory',function(){
var byte = 'dog';
var service = {
byte: byte,
getByte: getByte,
setByte: setByte
}
return service;
function getByte(){
return this.byte;
}
function setByte(value){
this.byte = value;
}
})
.controller('fooFail', function(binFactory,$scope){
$scope.setBin = binFactory.setByte;
$scope.value = binFactory.byte; //remeber, binding to object props break the reference and sync won't work anymore
})
.controller('barFail', function(binFactory,$scope){
$scope.value = binFactory.byte;
$scope.setBin = setBin;
function setBin(){
binFactory.setByte($scope.value)
}
})
</script>
<script id="jsbin-source-javascript" type="text/javascript">angular.module('myApp',[])
.controller('foo', function(binFactory,$scope){
$scope.binValue = binFactory;
$scope.setBin = setBin;
$scope.value = 'foo';
function setBin(){
binFactory.setByte($scope.value)
}
})
.controller('bar', function(binFactory,$scope){
$scope.binValue = binFactory;
})
.factory('binFactory',function(){
var byte = 'dog';
var service = {
byte: byte,
getByte: getByte,
setByte: setByte
}
return service;
function getByte(){
return this.byte;
}
function setByte(value){
this.byte = value;
}
})
.controller('fooFail', function(binFactory,$scope){
$scope.setBin = binFactory.setByte;
$scope.value = binFactory.byte; //remeber, binding to object props break the reference and sync won't work anymore
})
.controller('barFail', function(binFactory,$scope){
$scope.value = binFactory.byte;
$scope.setBin = setBin;
function setBin(){
binFactory.setByte($scope.value)
}
})</script></body>
</html>
Raw
jsbin.feciqatari.js
angular.module('myApp',[])
.controller('foo', function(binFactory,$scope){
$scope.binValue = binFactory;
$scope.setBin = setBin;
$scope.value = 'foo';
function setBin(){
binFactory.setByte($scope.value)
}
})
.controller('bar', function(binFactory,$scope){
$scope.binValue = binFactory;
})
.factory('binFactory',function(){
var byte = 'dog';
var service = {
byte: byte,
getByte: getByte,
setByte: setByte
}
return service;
function getByte(){
return this.byte;
}
function setByte(value){
this.byte = value;
}
})
.controller('fooFail', function(binFactory,$scope){
$scope.setBin = binFactory.setByte;
$scope.value = binFactory.byte; //remeber, binding to object props break the reference and sync won't work anymore
})
.controller('barFail', function(binFactory,$scope){
$scope.value = binFactory.byte;
$scope.setBin = setBin;
function setBin(){
binFactory.setByte($scope.value)
}
})
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