Getting Error "Uncaught ReferenceError: require is not defined" in AngularJS

add.js

var fs = require('fs');
var addData = " <book category='children'><title>Harry Potter</title><author>J K. Rowling</author><year>2005</year><price>29.99</price></book>";
var cursor = "//cursor";
addData += cursor;
//var ws = fs.createWriteStream('./new_xml.xml');           //creating new file in same folder.      
fs.exists("new_xml.xml", function (exists) {
    if (exists) {
        //Adding new node in existing xml file      
        fs.readFile("new_xml.xml", "utf-8", function (err, data) {
            if (err) {
                console.log(err);
                return;
            }
            var newData = data.replace(/\/\/cursor/, addData);
            fs.writeFile("new_xml.xml", newData, function (err) {
                if (err) {
                    console.log(err);
                    return;
                }
                console.log("XML node is added successfully........");
            });
            // console.log(data);      
        });
    } else {
        console.log("File not exists.................");
    }
});


new_xml.xml

<bookstore>
   <book category="cooking">
       <title lang="en">Everyday Italian</title>
       <author>Giada De Laurentiis</author>
       <year>2005</year>
       <price>30.00</price> </book>
   //cursor
</bookstore>



In this example before //cursor 1 book node is added after executing add.js.......in node js.....(using this command node add.js).

.
.
BUT
same code executed in visual studio (or in angular project) i'm getting error
.
Uncaught ReferenceError: require is not defined.


Can anyone  help me?