Object-Oriented JavaScript and Address Books

#javascript #codenewbie #webdev #beginners

Address Book: Objects Within Objects

Examples

Add contacts to an AddressBook with its constructor and prototype methods:

scripts.js

// Business Logic for AddressBook ---------
function AddressBook() {
  this.contacts = {};
}

AddressBook.prototype.addContact = function(contact) {
  this.contacts[contact.firstName] = contact;
}

// Business Logic for Contacts ---------
function Contact(firstName, lastName, phoneNumber) {
  this.firstName = firstName;
  this.lastName = lastName;
  this.phoneNumber = phoneNumber;
}

Contact.prototype.fullName = function() {
  return this.firstName + " " + this.lastName;
}

Unique IDs

Example

Here's how scripts.js will look by the end of the lesson:

scripts.js

// Business Logic for AddressBook ---------
function AddressBook() {
  this.contacts = {};
}

AddressBook.prototype.addContact = function(contact) {
  contact.id = this.assignId();
  this.contacts[contact.id] = contact;
}

AddressBook.prototype.assignId = function() {
  this.currentId += 1;
  return this.currentId;
}

// Business Logic for Contacts ---------
function Contact(firstName, lastName, phoneNumber) {
  this.firstName = firstName;
  this.lastName = lastName;
  this.phoneNumber = phoneNumber;
}

Contact.prototype.fullName = function() {
  return this.firstName + " " + this.lastName;
}

Finding and Deleting Contacts

Examples

Find a Contact:

AddressBook.prototype.findContact = function(id) {
  if (this.contacts[id] != undefined) {
    return this.contacts[id];
  }
  return false;
}

Delete a Contact:

AddressBook.prototype.deleteContact = function(id) {
  if (this.contacts[id] === undefined) {
    return false;
  }
  delete this.contacts[id];
  return true;
}