Type Alias JoinTableForeignKeys<J>

JoinTableForeignKeys: {
    [P in Exclude<keyof J, ExcludeKeys>]: [ExtractForeignKeyTarget<J[P]>] extends [
        never,
    ]
        ? never
        : P
}[Exclude<keyof J, ExcludeKeys>]

The foreign key properties of a join table: those whose declared type is a ForeignKey or NullableForeignKey, typed or bare.