Backbone.js unshift Collection

Last Updated : 12 Dec, 2022

The Backbone.js unshift Collection is used to add model at the beginning of a Collection. It takes model as the first parameter and options as the second parameter. In this article, we will discuss the Backbone.js unshift Collection.

Syntax:

collection. unshift( model, options );

Parameters:

model: This parameter is used to specify the model’s instance which is going to add to the collection.
options: This is an optional parameter regarding the model which is being added to the collection.

Example 1: In this example, we will illustrate The Backbone.js unshift collection. In this example, we will add 2 models using unshift in the collection.

HTML

<!DOCTYPE html>
<html>
 
<head>
    <title>BackboneJS unshift collection</title>
    <script src="https://code.jquery.com/jquery-2.1.3.min.js"
        type="text/javascript">
    </script>
    <script src=
"https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.2/underscore-min.js"
        type="text/javascript">
    </script>
    <script src=
"https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.2.2/backbone-min.js"
        type="text/javascript">
    </script>
</head>
 
<body>
    <h1 style="color: green;">
        GeeksforGeeks
    </h1>
 
    <h3>BackboneJS unshift collection</h3>
     
    <script type="text/javascript">
        var Book = Backbone.Model.extend();
 
        var books = Backbone.Collection.extend({
            model: Book
        });
 
        var Library = new books();
 
        var b1 = new Book({ 
            title: "catch-22", 
            Author: "Joshep Heller" 
        });
         
        var b2 = new Book({ 
            title: "Invisible Man", 
            Author: "Ralph Ellison" 
        })
 
        Library.unshift(b1);
        Library.unshift(b2);
 
        document.write("Values :  <br> ");
        document.write(JSON.stringify(Library));
    </script>
</body>
 
</html>

Output:

Backbone.js unshift collection

Example 2: In this example, we will again add two models at beginning of the collection.

HTML

<!DOCTYPE html>
<html>
 
<head>
    <title>BackboneJS unshift collection</title>
    <script src="https://code.jquery.com/jquery-2.1.3.min.js"
        type="text/javascript">
    </script>
    <script src=
"https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.2/underscore-min.js"
        type="text/javascript">
    </script>
    <script src=
"https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.2.2/backbone-min.js"
        type="text/javascript">
    </script>
</head>
 
<body>
    <h1 style="color: green;">
        GeeksforGeeks
    </h1>
 
    <h3>BackboneJS unshift collection</h3>
     
    <script type="text/javascript">
        var Book = Backbone.Model.extend();
 
        var books = Backbone.Collection.extend({
            model: Book
        });
 
        var Library = new books();
 
        var b1 = new Book({ 
            title: "catch-22", 
            Author: "Joshep Heller" 
        });
         
        var b2 = new Book({ 
            title: "Invisible Man", 
            Author: "Ralph Ellison" 
        })
 
        Library.unshift(b1);
        Library.unshift(b2);
 
        document.write("Values :  <br> ");
        document.write(JSON.stringify(Library));
 
        document.write("<br><br>");
 
        var b3 = new Book({
            title: "Wings of Fire", Author:
                "A. P. J. Abdul Kalam"
        });
        var b4 = new Book({
            title: "The Palace of Illusion",
            Author: "Chitra Banerjee"
        });
 
        Library.unshift(b3);
        Library.unshift(b4);
 
        document.write("Values again unshifted :  <br> ");
        document.write(JSON.stringify(Library))
    </script>
</body>
 
</html>