JS Practice — Built-in Objects

String.prototype.padStart() — fixed-width number formatting

📖 Usage Example

'5'.padStart(3, '0')       // → '005'
'hi'.padStart(5, '-')     // → '---hi'
'hello'.padStart(3)       // → 'hello'

Use padStart() to pad the beginning of a string with a fill character until it reaches the target length.

String.prototype.padStart() — Fixed-Width Formatting

Zero-padding is great for time values like hours and minutes.

Challenge: Implement formatTime(h, m) that formats hours and minutes as HH:MM.

formatTime(9, 5)  // → '09:05'
formatTime(12, 0) // → '12:00'

💡 Hints (1)