[mjlawson]

One of the things that's often not considered with these kind of interfaces, is whether or not they're actually possible. For instance, arg3 might only be true if arg1 is also true. Or arg3 may not be false if both arg1 and arg2 are also false.

Using object arguments is a great start, and I think using enums can also be powerful (if you're using string literal types). But often times I reach for explicit interfaces in these situations. IE:

type FooScenario = { arg1: true; arg2: true; arg3: true };

type BarScenario = { arg1: false; arg2: true; arg3: false; }

type Scenario = FooScenario | BarScenario;

...etc

This provides semantic benefits in that it'll limit the input to the function (forcing callers to validate their input), and it also provides a scaffold to build useful, complete test cases.