Generic parse function
So, want to used parse function by generic
export function parse<T = ParsedQuery>(query: string, options?: ParseOptions): T;
And the IDE can suggest the query object's properties.

I have also caught common case in practice. It would be really convenient to use this generic with static type checking.
On DefinitelyTyped there is a lint rule to guard against this, and I would not recommend adding this as it hides an unsafe cast. There is nothing at all that guarantees that active be a boolean, or even exist, at runtime.
If you want to do this in your code, you can always do queryString.parse('...') as Some, which shows that you are casting. Adding a type parameter for this really only hides the as Some part, and makes it easier to miss the unsafety here...
It's the same with JSON.parse, it doesn't take a type parameter.
@LinusU could you elaborate on why it would be unsafe? Could you not take the generic passed into the function & wrap a Partial around it?