Course Modules
Introduction to JavaScript
Learn the fundamentals of JavaScript programming language
What is JavaScript?
Setting up your development environment
Basic syntax and data types
Variables and constants
Objects and Arrays
Master JavaScript objects and arrays
Working with Arrays
Array Methods
Object Creation
Object Properties
Functions & Scope
Understanding functions and variable scope in JavaScript
Function declarations
Arrow functions
Function parameters
Variable scope and closures
Understanding Error Handling & Debugging
Error handling is crucial for writing robust JavaScript applications. Learning how to properly catch and handle errors, along with effective debugging techniques, will help you create more reliable code and solve problems more efficiently.
Try-Catch Statements
// Basic Try-Catch
try {
// Code that might throw an error
const result = someUndefinedVariable + 1;
} catch (error) {
console.error('An error occurred:', error.message);
}
// Try-Catch-Finally
try {
// Attempt to parse JSON
const data = JSON.parse('{"invalid": json}');
} catch (error) {
console.error('Parsing failed:', error);
} finally {
console.log('This runs regardless of success or failure');
}Error Types
// Common Error Types
// ReferenceError
try {
console.log(undefinedVariable);
} catch (error) {
console.log(error instanceof ReferenceError); // true
}
// TypeError
try {
null.toString();
} catch (error) {
console.log(error instanceof TypeError); // true
}
// SyntaxError
try {
eval('if (true) {');
} catch (error) {
console.log(error instanceof SyntaxError); // true
}Custom Errors
// Custom Error Class
class ValidationError extends Error {
constructor(message) {
super(message);
this.name = 'ValidationError';
}
}
// Using Custom Error
function validateUser(user) {
if (!user.name) {
throw new ValidationError('Name is required');
}
if (!user.email) {
throw new ValidationError('Email is required');
}
}
try {
validateUser({ name: '', email: '' });
} catch (error) {
if (error instanceof ValidationError) {
console.log('Validation failed:', error.message);
} else {
console.log('Unknown error:', error);
}
}Debugging Techniques
// Debugging Techniques
// Console Methods
console.log('Basic logging');
console.info('Information');
console.warn('Warning message');
console.error('Error message');
console.table([{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }]);
// Debugger Statement
function complexCalculation(x, y) {
debugger; // Code execution will pause here in dev tools
const result = x * y / (x - y);
return result;
}
// Performance Measurement
console.time('loop');
for (let i = 0; i < 1000000; i++) {
// Some operation
}
console.timeEnd('loop');