Free Range

Create a function which converts an ordered number array into a array of ranges (represented as strings). Note how some arrays have some numbers missing.

Examples

numbersToRanges([1, 2, 3, 4, 5]) ➞ ["1-5"]

numbersToRanges([3, 4, 5, 10, 11, 12]) ➞ ["3-5", "10-12"]

numbersToRanges([1, 2, 3, 4, 99, 100]) ➞ ["1-4", "99-100"]

numbersToRanges([1, 3, 4, 5, 6, 7, 8]) ➞ ["1", "3-8"]

Notes

• If there are no numbers consecutive to a number in the array, represent it as only the string version of that number (see example #4).
• Return an empty array if the given array is empty.