This type is a little wonky but basically it's saying that if RoleIdentifier is undefined, then this is a function with no props
And if RoleIdentifier is a string then this is a function with a single roleIdentifier prop
See https://github.com/Microsoft/TypeScript/pull/24897
This type is a little wonky but basically it's saying that if RoleIdentifier is undefined, then this is a function with no props And if RoleIdentifier is a string then this is a function with a single roleIdentifier prop See https://github.com/Microsoft/TypeScript/pull/24897