Convert type alias to interface?

[alloy]

TypeScript allows for declaration merging of interfaces, which appears to be something that people do to extend types for react-native-web, whereas this cannot be done with type aliases. So it might be preferable to convert to interfaces.

interface X { foo: string }
interface X { bar: string } // merge declaration
const x: X = { foo: "foo", bar: "bar" }

In case it makes things easier, perhaps as a first step, we could also create a temp type alias and use it to extend an empty interface with:

type $1 = { foo: string }
interface X extends $1 {}
interface X { bar: string } // merge declaration
const x: X = { foo: "foo", bar: "bar" }

[alloy]

This might be something we just do selectively using overrides. Cases like RN’s ViewProps definitely make sense from an error reporting perspective too. Errors where type aliases are involved show the full typing, whereas an interface shows only an interned name.

microsoft/TypeScript#13095

E.g.

Type '(Readonly<Readonly<{ onBlur?: ((event: Readonly<{ bubbles?: boolean | null | undefined; cancelable?: boolean | null | undefined; currentTarget: unknown; defaultPrevented?: boolean | null | undefined; dispatchConfig: Readonly<...>; ... 10 more ...; type?: string | ... 1 more ... | undefined; }>) => unknown) | null | ...' does not satisfy the constraint '{ readonly [$f2tKey: string]: unknown; }'.
  Type 'Readonly<Readonly<{ onBlur?: ((event: Readonly<{ bubbles?: boolean | null | undefined; cancelable?: boolean | null | undefined; currentTarget: unknown; defaultPrevented?: boolean | null | undefined; dispatchConfig: Readonly<...>; ... 10 more ...; type?: string | ... 1 more ... | undefined; }>) => unknown) | null | u...' is not assignable to type '{ readonly [$f2tKey: string]: unknown; }'.
    Index signature is missing in type 'Readonly<Readonly<{ onBlur?: ((event: Readonly<{ bubbles?: boolean | null | undefined; cancelable?: boolean | null | undefined; currentTarget: unknown; defaultPrevented?: boolean | null | undefined; dispatchConfig: Readonly<...>; ... 10 more ...; type?: string | ... 1 more ... | undefined; }>) => unknown) | null | u...'.

VS

Type '(ViewProps & { children?: ReactNode; } & RefAttributes<Readonly<NativeMethods>>) | (ViewProps & RefAttributes<...>)' does not satisfy the constraint '{ readonly [$f2tKey: string]: unknown; }'.
  Type 'ViewProps & { children?: ReactNode; } & RefAttributes<Readonly<NativeMethods>>' is not assignable to type '{ readonly [$f2tKey: string]: unknown; }'.
    Index signature is missing in type 'ViewProps & { children?: ReactNode; } & RefAttributes<Readonly<NativeMethods>>'.