JS Practice — Built-in Objects

String.prototype.concat() — concat with empty string

📖 Usage Example

const str = 'Hello'
str.concat(', ', 'World', '!')   // → 'Hello, World!'
''.concat('a', 'b', 'c')          // → 'abc'

Use concat() to join two or more strings together, returning a new string without modifying the originals.

String.prototype.concat() — Identity

Concatenating with an empty string returns a copy of the original.

Challenge: Implement withEmpty(str) that returns str.concat('').

withEmpty('hello') // → 'hello'

💡 Hints (1)