In this article, we will discuss Backbone.js length collection. The Backbone.js length collection is used to return the total number of elements/values present in the model collection.
Syntax:
Backbone.Collection.length
Parameters: It takes no parameters.
Example 1: In this example, we will create a model array with one element and return the length.
HTML
<!DOCTYPE html> < html >   < head >     < script type = "text/javascript" src =     </ script >     < script type = "text/javascript" src =       </ script >     < script type = "text/javascript" src =       </ script > </ head >   < body >     < script type = "text/javascript" >         var data = Backbone.Model.extend({             defaults: {                 id: "1",                 name: "sravan kumar gottumukkala",                 age: "67"             },         });           var data1 = Backbone.Collection.extend({             model: data         });           var final = new data1({});           document.write(           "Values:", JSON.stringify(final.toJSON())         );         document.write("< br >");         document.write("Length:", final.length);      </ script > </ body >   </ html > |
Output:
Values:[{"id":"1","name":"sravan kumar gottumukkala","age":"67"}] Length:1
Example 2: In this example, we will create a model array with four elements and return the length.
HTML
<!DOCTYPE html> < html >   < head >     < script type = "text/javascript" src =     </ script >     < script type = "text/javascript" src =       </ script >     < script type = "text/javascript" src =       </ script > </ head >   < body >     < script type = "text/javascript" >         var datas = Backbone.Model.extend({             defaults: {                 name: "sravan"             }         });           var datacollection = Backbone.Collection.extend({             model: datas         });           var data1 = new datas({ name: "ram" });         var data2 = new datas({ name: "shivam" });         var data3 = new datas({ name: "ramya" });         var data4 = new datas({ name: "deepu" });           var final = new datacollection();         final.add([data1, data2, data3, data4]);           document.write(           "Values:", JSON.stringify(final.toJSON())         );         document.write("< br >");         document.write("Length:", final.length);      </ script > </ body >   </ html > |
Output:
Values:[{"name":"ram"},{"name":"shivam"},{"name":"ramya"},{"name":"deepu"}] Length:4
Reference: https://backbonejs.org/#Collection-length