Console & Debugging
What is the Console?
The browser console is a powerful tool for viewing output, testing code, and debugging. It's your best friend when learning JavaScript!
console.log() - Your Debugging Companion
console.log() prints messages to the console. Use it to check
variable values, track code execution, and debug issues.
Other Console Methods
The console has many useful methods beyond log(). Each
serves a specific purpose!
Console Method Reference
| Method | Purpose | Example |
|---|---|---|
log()
|
General output |
console.log('Hi')
|
error()
|
Error messages |
console.error('Oops!')
|
warn()
|
Warnings |
console.warn('Careful')
|
table()
|
Display as table |
console.table(data)
|
clear()
|
Clear console |
console.clear()
|
Debugging with console.log()
Use console.log() strategically to track down bugs and
understand code flow.
Common Debugging Techniques
1. Check Variable Values
const result = calculateTotal();
console.log('Result:', result);2. Track Function Execution
function processData() {
console.log('processData started');
// ... code ...
console.log('processData finished');
}3. Inspect Objects
const user = { name: 'Alice', age: 25 };
console.log('User object:', user);4. Check Data Types
const value = '42';
console.log('Type:', typeof value);console.log() statements before deploying to
production!
Summary
- The console is essential for debugging JavaScript
console.log()displays values and messages- Use
console.error()for errors,console.warn()for warnings console.table()displays arrays/objects as tables- Strategic logging helps track code execution and find bugs
- Open console with F12 or Ctrl+Shift+I
Quick Quiz
Which console method displays data in a table format?
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