Duplicate elements
Return the given string with 2 occurrences for each elements.
Sample Code:
function doubleUp(str) {
// Enter your logic here...
}
Examples:
Input: 'Hello World'
Output: 'HHeellllloo WWoorrlldd'
Explanation: Every Elements have its own duplication.
Input: 'ಠ_ಠ'
Output: 'ಠಠ__ಠಠ'
Explanation: Symbols are also being duplicated.
