Is it necessary to specify the type?

Question

typescript

Please tell me in this code:

ColorScheme = 'primary'|'accent'|'warn';
.....
@Input() public color: ColorScheme|null = null;

is it necessary to specify the type with: The fact is that if I remove |null , then there are no error messages in the console
|null

Answer 1

When how :

By default nulland undefinedare subtypes of all other types.
<...>
However, when using the --strictNullChecksflag, nulland undefinedare only assignable to any and their respective types