JS Practice — Built-in Objects

String.prototype.toUpperCase() — empty string

📖 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() — Empty String

Calling toUpperCase() on an empty string returns an empty string.

Challenge: Implement safeUpper(str) using toUpperCase.

safeUpper('') // → ''
safeUpper('hi') // → 'HI'

💡 Hints (1)