Step 1 open usersjs in the routes directory and add

Step 1 : Open users.js in the ./routes directory and add the following middleware:
/*
* PUT to updateContact

*/
router.put('/updateContact/:id', function (req, res) {
var db = req.db;
var collection = db.get('contactList');
var contactToUpdate = req.params.id;
//TO DO: update the contact record in contactList collection, according to contactToUpdate
and data included in the body of the HTTP request
});
Implement the code in the above middleware, for updating an existing contact record in
the contactList collection, whose “_id” is carried in the URL of the PUT request, and new
contact information carried in request body. Hint : use collection.update() . Upon successful
update, the server should send a response message back to the client with an empty body;
otherwise, it sends the error message back to the client.
Step 2 : Open externalJS.js in the ./public/javascripts/ directory and add the following code
at the end of the file to update the contact record when an existing contact record is
updated.
// Update Contact
function updateContact(existingContact) {
var id = existingContact._id;
$.ajax({
type: ?,
url: ?,
data: ?,
dataType: 'JSON'
}).done(function (response) {
if (response.msg === '') {
// Clear the form inputs
?
// Update the table
populateContactList();
//Update detailed info if the updated contact's detailed info is displayed
?
}
else {
?
}
});
};
Replace “?” with correct code to finish the client-side code for sending an AJAX HTTP PUT
request and handling the response. Upon successful update, you should clear the form input
on the web page; and if the detailed contact information of the updated contact is being

displayed under “Contact Info”, update the contact info there. If an error message is carried in
the response, prompt the error message using alert() .
Step 3 : Restart your Express app, browse again, and test the update
function as follows:
Fig. 6 Input new information of Fig. 7 After clicking
an existing contact “Add/Update Contact”
on the Fig. 6 view
Lab Exercise 6: Delete a Contact
In this part, we implement the server-side and client-side code for deleting a contact record
from the database, when a respective “delete” button in the contact list is clicked.
Step 1 : Open users.js in the ./routes directory and add the following middleware:
/*
* DELETE to delete a contact.
*/
router.delete(?, function(req, res) {
?
});
You should replace “?” with correct code for handling a delete request, by following the
hints below:
1. Among the code we added in Step 4 of Lab Exercise 2, the “_id” attribute of a contact
record is saved to the “rel” attribute of a “<a>” element of class “linkDeleteContact” , i.e.,
the “ delete ” link shown in the screenshots. The client will send an AJAX HTTP DELETE
request to the following URL once you click the “ delete” button:
(replace xx by the value of “_id” attribute of a contact record to be deleted).

2. The middleware should handle HTTP DELETE requests for path /deleteContact/:id,
and retrieve the “_id” attribute carried in a DELETE request through req.params.id .