The Backbone.js extend Model is used to extend the backbone’s Model class in which we can create our own Model. It also facilitates the instance properties & the optional classProperties that are attached to the constructor function of the Model directly. Extend method of the model create a prototype chain, so subclass created with extend can be further extended and subclassed as far as you like.
Syntax:
Backbone.Model.extend( Properties, classProperties );
Parameters: It accepts two parameters that are described below:
- Parameters: This parameter provides the instance properties for the specified collection class.
- classProperties: This class property is attached to the collection’s constructor function.
Example 1: In this example, we will extend a Model with some default values.
<!DOCTYPE html> <html>
<head>
<title>BackboneJS Model extend</title>
<script src=
</script>
<script src=
type="text/javascript">
</script>
<script src=
type="text/javascript">
</script>
</head>
<body>
<h1 style="color: green;">
GeeksforGeeks
</h1>
<h3>BackboneJS Model extend</h3>
<script type="text/javascript">
var model = Backbone.Model.extend({
defaults: {
id: 1,
name: 'Geeks'
},
});
var temp = new model();
document.write(JSON.stringify(temp));
</script>
</body>
</html>
|
Output:
Backbone.Model.extend()
Example 2: In this example, we will make a chain of extend function and see the properties of each object. Extend method of model create a prototype chain, so subclass created with extend can be further extended and subclassed as far as you like.
<!DOCTYPE html> <html>
<head>
<title>BackboneJS Model extend</title>
type="text/javascript">
</script>
<script src=
type="text/javascript">
</script>
<script src=
type="text/javascript">
</script>
</head>
<body>
<h1 style="color: green;">
GeeksforGeeks
</h1>
<h3>BackboneJS Model extend chaining</h3>
<script type="text/javascript">
var model = Backbone.Model.extend({
defaults: {
id: -1,
name: 'Geeks'
},
});
var temp = new model();
document.write(JSON.stringify(temp));
var model2 = model.extend({
initialize: function () {
document.write(
"<br> This function is extend by second extend");
},
});
var temp2 = new model2({ id: 2, name: 'cody' });
document.write("<br>", JSON.stringify(temp2));
</script>
</body>
</html>
|
Output:
Model.extend() chaining
Reference: https://backbonejs.org/#Model-extend