JS Practice — Built-in Objects

String.prototype.toUpperCase() — numbers and symbols unchanged

📖 Usage Example

'hello world'.toUpperCase()   // → 'HELLO WORLD'
'abc'.toUpperCase()           // → 'ABC'
'xyz123'.toUpperCase()        // → 'XYZ123'

Use toUpperCase() to convert all alphabetical characters in a string to uppercase.

String.prototype.toUpperCase() — Numbers Unchanged

Digits, spaces, and symbols are not affected by toUpperCase().

Challenge: Implement upperAlpha(str) that uppercases only the letters.

upperAlpha('abc 123!') // → 'ABC 123!'

💡 Hints (1)

• Only letter characters are converted; numbers, symbols, and spaces are left as-is.