JS Practice — Built-in Objects

String.prototype.padStart() — zero-pad numbers

📖 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()

str.padStart(targetLength, padString?) pads the start of str with padString (default: space) until the total length reaches targetLength.

Challenge: Implement zeroPad(n, width) that zero-pads a number to the given width.

zeroPad(5, 3)  // → '005'
zeroPad(42, 4) // → '0042'

💡 Hints (1)