function reverse_t9(keys) { /*landline and some mobile phones have letters on their numbers corresponding to particular letters. for some old flip phones, to type letters, you had to press the number corresponding to the letter to get that particular letter.
write a function that emulates this functionality. for example, 22 is b, 666 is o, 9999 is z.
Here is a list of letters on each number 2 is abc 3 is def 4 is ghi 5 is jkl 6 is mno 7 is pqrs 8 is tuv 9 is wxyz
if two letters would require the same sequential number, like a followed by b, a space will separate them. for example 2 222 22 would be acb 22334 would be beg */ } console.log(reverse_t9('44 444 44666 9 277733 999666888')); //hihowareyou
solution : http://jsbin.com/butapi/edit?js,console