Bug: Interface 'DayPickerSingleProps' incorrectly extends interface 'DayPickerBase'

[claviustales]

Bug description

Compiling a project that uses TypeScript 4.6.4, get the following:

node_modules/react-day-picker/dist/types/DayPickerSingle.d.ts:6:18 - error TS2430: Interface 'DayPickerSingleProps' incorrectly extends interface 'DayPickerBase'.
  Types of property 'selected' are incompatible.
    Type 'Date | undefined' is not assignable to type 'Matcher | Matcher[]'.
      Type 'undefined' is not assignable to type 'Matcher | Matcher[]'.

To reproduce

I could not reproduce on CodeSandbox.

[gpbl]

@claviustales please provide some context:

• some code to investigate :)
• are you migrating from v7?

[claviustales]

Hi, @gpbl.

As you intuited, I'm migrating from v7. I've followed the guide. I'm using yarn. The problem occurs when I run yarn compile.

About sharing coding: as shown on problem description, the issue is not on my code; it's on lib code.

It is simple to see the problem on lib code:

On this file:

export interface DayPickerBase {
  ...
  selected?: Matcher | Matcher[];
  ...
}

On this file:

export interface DayPickerSingleProps extends DayPickerBase {
  ...
  selected?: Date | undefined;
  ...
}

The second interface inherits from the first interface and "redefine" the type of selected property, that is not allowed by TypeScript.

[gpbl]

The second interface inherits from the first interface and "redefine" the type of selected property, that is not allowed by TypeScript.

That should not be the case, as Date is a subset of Matcher.

• what does yarn compile do?
• did you remove the previous types?
• which version of typescript are you using?

[claviustales]

That should not be the case, as Date is a subset of Matcher.

Because of that your statement, I've got the real problem:

In my project, exactOptionalPropertyTypes compile option is turned on. In this case, Date | undefined is not a subset of Matcher, as Matcher does not include undefined.

[gpbl]

Oh that is interesting. I guess if we add undefined to

react-day-picker/packages/react-day-picker/src/types/DayPickerBase.ts

Line 186 in 77bbb66

selected?: Matcher | Matcher[];

the problem should go away.

[claviustales]

Exactly. This would be my suggestion.