JS Practice — Built-in Objects

String.prototype.concat() — multiple strings

📖 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() — Multiple Arguments

.concat() accepts multiple arguments and joins them all.

Challenge: Implement joinAll(parts) that calls ''.concat(...parts).

joinAll(['Hello', ', ', 'World', '!']) // → 'Hello, World!'

💡 Hints (1)