Answers

1. The flag variable would be inferred to be a boolean type.
2. The return type in the function is void.
3. An array of dates can be represented as Date[] or Array<Date>.
4. A type error will not be raised on the point variable. It doesn’t need to include the z property because it is optional.
5. A type for numbers 1-3 can be created as follows:

   type OneToThree = 1 | 2 | 3;

6. The noEmitOnError compiler option (set to true) can be used to prevent the transpilation process when a type error is found.
7. A union type can be used for the lastSale property to allow it to accept null values:

   type Product = {

     name: string;

     lastSale: Date | null;

   }

   const table: Product = {name: "Table", lastSale: null}