String.prototype.repeatbeginner'ab'.repeat(3) // β 'ababab'
'-'.repeat(5) // β '-----'
'x'.repeat(0) // β ''Use repeat() to create a new string with the original repeated a specified number of times.
Calling .repeat(0) always returns an empty string regardless of the original string.
Challenge: Implement isRepeatEmpty(str) that returns true if repeating str zero times gives an empty string.
isRepeatEmpty('hello') // β true
isRepeatEmpty('') // β true