Debugging JavaScript Like a Pro: Complete Guide

JavaScript Debugging Mastery

Effective debugging saves hours of frustration. Master these techniques.

Console Methods

console.log('Basic output');
console.error('Error message');
console.warn('Warning');
console.table([{a: 1}, {a: 2}]); // Table format
console.time('timer');
// ... code ...
console.timeEnd('timer'); // Shows execution time

Chrome DevTools

Breakpoints

• Click line number to add breakpoint
• Conditional breakpoints for specific cases
• DOM breakpoints for element changes

Network Tab

• Inspect API requests/responses
• Check loading times
• Simulate slow connections

Common Debugging Patterns

// Check if value exists
console.log('user:', user ?? 'undefined');

// Trace function calls
console.trace('How did we get here?');

// Group related logs
console.group('User Data');
console.log('Name:', user.name);
console.log('Email:', user.email);
console.groupEnd();

VS Code Debugging

1. Add launch.json configuration
2. Set breakpoints in editor
3. Press F5 to start debugging
4. Use watch expressions

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