Object use cases in Javascript - Mini Project: Build & Apply

Object use cases

📖 Scenario: You are building a simple contact list app. Each contact has a name and a phone number. You want to store these contacts in an object for easy lookup and management.

🎯 Goal: Create an object to store contacts, add a new contact, retrieve a contact's phone number, and display the contact list.

📋 What You'll Learn

Create an object called contacts with two contacts and their phone numbers.

Create a variable called newContactName with the value 'Emma' and a variable called newContactNumber with the value '555-0199'.

Add the new contact to the contacts object using the variables newContactName and newContactNumber.

Use a for...in loop to print each contact's name and phone number in the format: Name: PhoneNumber.

💡 Why This Matters

🌍 Real World

Objects are used to store and manage related data like contacts, products, or settings in many apps.

💼 Career

Understanding objects and how to manipulate them is essential for web development and working with data in JavaScript.

1

Create the initial contacts object

Create an object called contacts with these exact entries: 'Alice': '555-1234' and 'Bob': '555-5678'.

Javascript

// Create the contacts object with Alice and Bob
// Your code here

Need a hint?

Use curly braces {} to create an object and add key-value pairs for Alice and Bob.

2

Add new contact variables

Create a variable called newContactName with the value 'Emma' and a variable called newContactNumber with the value '555-0199'.

Javascript

const contacts = {
  'Alice': '555-1234',
  'Bob': '555-5678'
};

// Create newContactName and newContactNumber variables
// Your code here

Need a hint?

Use const to create variables for the new contact's name and number.

3

Add the new contact to the contacts object

Add the new contact to the contacts object using the variables newContactName and newContactNumber.

Javascript

const contacts = {
  'Alice': '555-1234',
  'Bob': '555-5678'
};

const newContactName = 'Emma';
const newContactNumber = '555-0199';

// Add the new contact to contacts
// Your code here

Need a hint?

Use bracket notation with the variable newContactName to add the new contact to the object.

4

Print all contacts

Use a for...in loop with the variable name to print each contact's name and phone number in the format: Name: PhoneNumber.

Javascript

const contacts = {
  'Alice': '555-1234',
  'Bob': '555-5678'
};

const newContactName = 'Emma';
const newContactNumber = '555-0199';

contacts[newContactName] = newContactNumber;

// Use for...in loop to print all contacts
// Your code here

Need a hint?

Use for (const name in contacts) and console.log with template strings to print each contact.