Thank you for creating a Pull Request @Mnickii.

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@sebastienlevert from your proposal you'd suggested using personType as the property added, but Person entity already has personType as a property , which can be of a class Person or Group.
I've renamed this to entityType that can be "user" | "people" | "group", would this work? Then it can be set where "personType in personDetails" as entityType: person and "groupTypes in personDetails" as entityType:group cc @gavinbarron

Renaming means breaking change. @gavinbarron do you have a suggestion for this case? We need to identify a way to know if a picked entity is a group or a person.

The updated storybook is available here

The updated storybook is available here

Renaming means breaking change. @gavinbarron do you have a suggestion for this case? We need to identify a way to know if a picked entity is a group or a person.

Adding a new property, which is what I think @Mnickii has done is not a breaking change though.

Adding to the type guard idea you can factor out the typing even further:

type IUser = (MicrosoftGraph.User | MicrosoftGraph.Person) & { entityType: 'user' }
type IContact = MicrosoftGraph.Contact & { entityType: 'contact' }
type IGroup MicrosoftGraph.Group & { entityType: 'group' }

export type IDynamicPerson = (
  IUser
  | IContact
  | IGroup
) & {
  /**
   * personDetails.personImage is a toolkit injected property to pass image between components
   * an optimization to avoid fetching the image when unnecessary.
   *
   * @type {string}
   */
  personImage?: string;
};

isGroup = (obj: IDynamicPerson): obj is Group => {
    return entityType === 'group';
};

Actually, on reflection, perhaps the better approach here is to provide an exported isGroup type guard function for developers to use should they need to determine an object emitted in an event is a group or not? Thoughts?

I like this last proposal @gavinbarron!

The updated storybook is available here

The updated storybook is available here

The updated storybook is available here

The updated storybook is available here

To illustrate this scenario, could we build a simple story?

The updated storybook is available here

The updated storybook is available here

The updated storybook is available here

The updated storybook is available here