The `options` arg of `Temporal.ZonedDateTime.prototype.toLocaleString()` currently accepts "illegal" option `timeZone`

⚙ Compilation target

ESNext

⚙ Library

ESNext

Missing / Incorrect Definition

https://github.com/microsoft/TypeScript/blob/0b832e12235cc3db14a4be6501827c2f8a8a8569/tsc/internal/bundled/libs/lib.esnext.temporal.d.ts#L320

Sample Code

TypeScript allows the following code, when it should not.

Temporal.Now.zonedDateTimeISO("America/Chicago").toLocaleString(undefined, { timeZone: "Europe/Berlin" });

Result

Documentation Link

According to MDN:

The timeZone option must not be provided, as it is automatically set to be the date-time's timeZoneId.

The type definitions should be changed to

declare namespace Temporal {
  // ...
  interface ZonedDateTimeToLocaleStringOptions extends Omit<Intl.DateTimeFormatOptions, "timeZone"> {}
  // ...
  interface ZonedDateTime {
    // ...
    toLocaleString(locales?: Intl.LocalesArgument, options?: ZonedDateTimeToLocaleStringOptions): string;
  }
}