We need to create validators for each status. The validator will check if transition from current state is allowed or not.

function createValidator(state) {
  return function(currentState) {
    return currentState === state;
  }
}

var isClosed = createValidator('closed');
var isPending = createValidator('pending');
var isOpen = createValidator('open');


// Usage
isClosed('closed'); // true
isClosed('pending'); // false
isClosed('open'); // false