JS Practice — Built-in Objects

String.prototype.toLowerCase() — mixed case to lowercase

📖 Usage Example

'HELLO World'.toLowerCase()   // → 'hello world'
'ABC'.toLowerCase()           // → 'abc'
'XYZ123'.toLowerCase()        // → 'xyz123'

Use toLowerCase() to convert all alphabetical characters in a string to lowercase.

String.prototype.toLowerCase() — Mixed Case

All uppercase letters in a mixed string are converted to lowercase.

Challenge: Implement normalize(str) that normalizes case to lowercase.

normalize('HeLLo WoRLd') // → 'hello world'

💡 Hints (1)

• `toLowerCase()` only affects uppercase letters — other characters are unchanged.