var NumberArray = function (start, end, prefix, suffix){ 
var result = [] ; 
for (var i = start; 
i <= end; i++ ){ 
if (prefix || suffix) { 
var key = (prefix)? prefix + i.toString(): i.toString(); 
if (suffix) { 
key = key.concat(suffix); 
} 
result.push(key); 
} 
 else { 
result.push(i); 
} 
} 
return result; 
} 
; 
module.exports = NumberArray;