Exercise 1: Declaring Variables
Problem: Create three variables: a string named city, a number named population, and a boolean named isCapital. Assign appropriate values to them.
Explanation: This exercise helps understand the basic syntax for variable declaration in JavaScript using let or const. Variables are used to store data values.
Code:
let city = ‘New York’;
let population = 8419000;
let isCapital = false;
Exercise 2: Changing Variable Types
Problem: Declare a variable data and assign it a number. Then change its value to a string and log its type to the console.
Explanation: JavaScript variables are dynamically typed, meaning they can hold values of any type without any type enforcement.
Code:
let data = 42;
data = ‘Now I am a string’;
console.log(typeof data); // Should print ‘string’
Exercise 3: Understanding Const
Problem: Declare a constant PI and assign it the value of 3.14159. Try to reassign a new value to PI and observe what happens.
Explanation: const is used for declaring constants which are not supposed to change after their initial assignment.
Code:
const PI = 3.14159;
// PI = 3.14; // This line should cause an error when uncommented
Exercise 4: Working with Arrays
Problem: Create an array named colors containing three strings representing colors. Access the second item in the array and print it to the console.
Explanation: Arrays are used to store multiple values in a single variable and are accessed using index numbers.
Code:
let colors = [‘red’, ‘green’, ‘blue’];
console.log(colors[1]); // Accesses and prints ‘green’
Exercise 5: Object Properties
Problem: Create an object named car with properties make, model, and year. Log the model to the console.
Explanation: Objects are collections of properties, where each property is a key-value pair.
Code:
let car = {
make: ‘Toyota’,
model: ‘Corolla’,
year: 2020
};
console.log(car.model); // Accesses and prints ‘Corolla’
Exercise 6: Using Null
Problem: Declare a variable unfinished and initialize it with null. Explain the significance of the value null in JavaScript.
Explanation: null in JavaScript is used to represent the intentional absence of any object value.
Code:
let unfinished = null;
// null is used to signify that ‘unfinished’ intentionally has no value
Exercise 7: Understanding Undefined
Problem: Declare a variable box. Log its value to the console without initializing it.
Explanation: Variables in JavaScript that are declared but not initialized have the value undefined.
Code:
let box;
console.log(box); // Should print ‘undefined’
Exercise 8: Concatenating Strings
Problem: Create two string variables, firstName and lastName. Combine them into a third variable fullName and print it.
Explanation: String concatenation is the process of joining two or more strings together.
Code:
let firstName = ‘John’;
let lastName = ‘Doe’;
let fullName = firstName + ‘ ‘ + lastName;
console.log(fullName);
Exercise 9: String and Number Interaction
Problem: Create a variable basePrice as a number and a variable taxRate as a decimal. Compute the total price and convert it to a string with a dollar sign in front.
Explanation: This exercise demonstrates type coercion between numbers and strings as well as basic arithmetic operations.
Code:
let basePrice = 50;
let taxRate = 0.05;
let totalPrice = basePrice * (1 + taxRate);
let displayPrice = ‘$’ + totalPrice.toFixed(2);
console.log(displayPrice);
Exercise 10: Boolean Logic
Problem: Create two boolean variables, isAdult and hasConsent. Create a new variable canProceed that checks if either condition is true.
Explanation: This exercise helps understand logical operators and boolean logic in JavaScript.
Code:
let isAdult = true;
let hasConsent = false;
let canProceed = isAdult || hasConsent;
console.log(canProceed); // Should print true
