Backbone.js has Model

0 0 1 minute read

In this article, we will see the Backbone.js has() model. The Backbone.js has() model is used to check if an attribute contains value or not. if the value exists or it’s a not-null value, it will return “true”, if it is null, it will return “false”.

Syntax:

Backbone.Model.has(attribute);

Parameters: It accepts one parameter:

attribute: It specifies the attribute in a model.

Example 1: Check whether the model book attributes have values or not by using has() model.

HTML

<!DOCTYPE html> 
<html> 
  
<head> 
    <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/1.1.2/backbone-min.js"
            type="text/javascript"> 
    </script>     
</head> 
  
<body> 
    <script type="text/javascript">   
        var Books = Backbone.Model.extend();   
        var book = new Books({bookid:null,price:null,book_name:null});  
             
        document.write(" bookid is not-null? : ",book.has('bookid')); 
        document.write("<br>"); 
        document.write(" price is not-null? : ",book.has('price')); 
        document.write("<br>"); 
        document.write(" book_name is not-null? : ",book.has('book_name'));  
    </script>  
</body> 
</html>

Output:

bookid is not-null? : false
price is not-null? : false
book_name is not-null? : false

Example 2: It checks whether the model book has values or not.

HTML

<!DOCTYPE html> 
<html> 
  
<head> 
    <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/1.1.2/backbone-min.js"
            type="text/javascript"> 
    </script>     
</head> 
  
<body> 
    <script type="text/javascript">   
        var Books = Backbone.Model.extend();   
        var book = new Books({bookid:6,price:4555,book_name:'php'});  
             
        document.write(" bookid is not-null? : ",book.has('bookid')); 
        document.write("<br>"); 
        document.write(" price is not-null? : ",book.has('price')); 
        document.write("<br>"); 
        document.write(" book_name is not-null? : ",book.has('book_name')); 
    </script>  
</body> 
</html>

Output:

bookid is not-null? : true
price is not-null? : true
book_name is not-null? : true

Reference: https://backbonejs.org/#Model-has

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