Dart null / false / empty checking: How to write this shorter?

Question

This is my code for true on everything but empty string, null and false:

if (routeinfo[\"no_route\"] == \"\" || routeinfo[\"no_route\"] == null || routeinfo[         


        

Answer 1

I would write a helper function instead of doing everything inline.

bool isNullEmptyOrFalse(Object o) =>
  o == null || false == o || "" == o;

bool isNullEmptyFalseOrZero(Object o) =>
  o == null || false == o || 0 == o || "" == o;

That avoids the repeated lookup (like the contains operation), but it is much more readable. It also doesn't create a new List literal for each check (making the list const could fix that).

if (isNullEmptyOrFalse(routeinfo["no_route"])) { ... }

When struggling with making something short and readable, making a well-named helper function is usually the best solution.

(Addition: Now that Dart has extension methods, it's possible to add the functionality as methods or getters that are seemingly on the object, so you can write value.isNullOrEmpty directly).