Split the State type into ScenariosStateRoot and ScenariosStateDerived

index.ts

@@ -25,19 +25,31 @@ export type CallbackMutateProject = (project: Project) => void | Promise<void>;
 
 export { Project };
 
-type State =
-  | {
-      type: 'root';
-      callbackCreateProject: CallbackCreateProject;
-    }
-  | {
-      type: 'derived';
-      parent: Scenarios;
-      variants: Record<string, CallbackMutateProject[]>;
-    };
+/**
+ * One of possible arguments used to instantiate {@link Scenarios}.
+ * 
+ * Normally you don't need this as {@link Scenarios} is not supposed to be instantiated by hand.
+ * Instead, you use its static methods.
+ */
+export interface ScenariosStateRoot {
+  type: 'root';
+  callbackCreateProject: CallbackCreateProject;
+}
+
+/**
+ * One of possible arguments used to instantiate {@link Scenarios}.
+ * 
+ * Normally you don't need this as {@link Scenarios} is not supposed to be instantiated by hand.
+ * Instead, you use its static methods.
+ */
+export interface ScenariosStateDerived  {
+  type: 'derived';
+  parent: Scenarios;
+  variants: Record<string, CallbackMutateProject[]>;
+}
 
 export class Scenarios {
-  private constructor(private state: State) {}
+  private constructor(private state: ScenariosStateRoot | ScenariosStateDerived) {}
 
   static fromDir(appPath: string, as: 'app' | 'lib' = 'app'): Scenarios {
     return new this({