How to create a type definition for an array of objects without using any[]?

I am using the date-fns library to get the months between a couple of date values using the eachMonthOfInterval function, like so:

const startingMonth = "2024-10-01 00:00:00";
const endingMonth = "2024-12-01 00:00:00";
const allMonths: any[] = eachMonthOfInterval(
  {
    start: startingMonth,
    end: endingMonth,
  },
  {
    in: tz("Asia/Calcutta"),
  }
);
console.log(allMonths);
console.log(allMonths[0].internal);

I am using the tz function from the library "@date-fns/tz" to specify the time zone in which I want the result (in this case, "Asia/Calcutta").

The following is the console.log that I get:

[
  TZDate 2024-09-30T18:30:00.000Z {
    timeZone: 'Asia/Calcutta',
    internal: 2024-10-01T00:00:00.000Z
  },
  TZDate 2024-10-31T18:30:00.000Z {
    timeZone: 'Asia/Calcutta',
    internal: 2024-11-01T00:00:00.000Z
  },
  TZDate 2024-11-30T18:30:00.000Z {
    timeZone: 'Asia/Calcutta',
    internal: 2024-12-01T00:00:00.000Z
  }
]
2024-10-01T00:00:00.000Z

Insted of any[], I tried using the type TZDate from the "@date-fns/tz" library, but I get this red squiggly line under the property internal in the line console.log(allMonths[0].internal)

When I hover on the red squiggly line, it says "Property 'internal' does not exist on type 'TZDate'."

How can I add a type to the constant allMonths without using the type any?

internal is not a property of TZDate. It only adds in runtime and should not be used in external functions. If you want to convert TZDate to Date or formatted string, use its functions instead of accessing to internal.

for (const month of allMonths) {
  console.log(month.toISOString());
}