add  "type checking"
UMix.is.type( value , typeString , isError , message );
-typeString = String types with special characters. A space separated.Examples :
-- "string"    is like typeof(value) == "string"
-- "!string" is like typeof(value) != "string"
-- "!customType" is like typeof(value) != "!customType"
-- "*Date"   is like  value instanceof Date
-- "=null" is like    value == null
-- "!*Date string !=null"    space separate

-isError = if "true"  , throw string. If message is string , throw message, else defined message.

Example : 
UMix.is.type( {hello : "world" } , "object !=null" , true  ); // return true;
UMix.is.type( null , "object !=null" , true  , "bad object"); // throw  "bad object"