Add types to all files and enable noImplicitAny

Continue where #74 left off by adding parameter and return
types to the rest of (non-ecmascript.ts) Temporal source files.

Also, turn on `noImplicitAny`.  Except for calendar.ts, this PR
removes `any` (implicit or otherwise) from the polyfill, with only
a few exceptions for truly generic code or testing propeties on
`globalThis`.

For calendar.ts, `any` is removed from the top level `Calendar`
implementation and some of the `impl[]` code, but fully
declaring all types in that file was more work than I wanted to
take on in this PR. So I did an initial pass on obvious types and
assigned a lot of `any` for the rest. Will definitely need a followup
PR to improve calendar.ts. @12wrigja has discussed the possibility
of replacing the old-school inheritance using Object.apply with a
modern `class`-based implementation. If we're going to do that,
then it may make sense to fix the types then instead of on top of
the current solution.

Aside from calendar.ts, there's still lots of TS work remaining
(e.g. `strictNullChecks`, `strictPropertyInitialization`), but at least
we'll now have valid types on all functions.

I didn't find any runtime errors as a result of this work (good!) but I
did find quite a few problems with the public types in index.d.ts, and
this PR fixes those too. Once the dust settles and the changes are
reviewed, I can port a change back to proposal-temporal to keep
all public types in sync.

Author: justingrant

.eslintrc.yml

@@ -79,6 +79,9 @@ rules:
   space-infix-ops: error
   '@typescript-eslint/explicit-module-boundary-types': off
   '@typescript-eslint/no-empty-function': off
+  '@typescript-eslint/no-empty-interface':
+    - error
+    - allowSingleExtends: true
   '@typescript-eslint/no-var-requires': off
   '@typescript-eslint/ban-ts-comment': off
   '@typescript-eslint/no-explicit-any': off # TODO turn this back on

index.d.ts

@@ -606,6 +606,7 @@ export namespace Temporal {
     fields?(fields: Iterable<string>): Iterable<string>;
     mergeFields?(fields: Record<string, unknown>, additionalFields: Record<string, unknown>): Record<string, unknown>;
     toString(): string;
+    toJSON?(): string;
   }
 
   /**
@@ -683,6 +684,7 @@ export namespace Temporal {
     fields(fields: Iterable<string>): Iterable<string>;
     mergeFields(fields: Record<string, unknown>, additionalFields: Record<string, unknown>): Record<string, unknown>;
     toString(): string;
+    toJSON(): string;
     readonly [Symbol.toStringTag]: 'Temporal.Calendar';
   }
 
@@ -990,14 +992,8 @@ export namespace Temporal {
     readonly calendar: Temporal.Calendar;
     equals(other: Temporal.PlainTime | PlainTimeLike | string): boolean;
     with(timeLike: Temporal.PlainTime | PlainTimeLike, options?: AssignmentOptions): Temporal.PlainTime;
-    add(
-      durationLike: Temporal.PlainTime | Temporal.Duration | DurationLike | string,
-      options?: ArithmeticOptions
-    ): Temporal.PlainTime;
-    subtract(
-      durationLike: Temporal.PlainTime | Temporal.Duration | DurationLike | string,
-      options?: ArithmeticOptions
-    ): Temporal.PlainTime;
+    add(durationLike: Temporal.Duration | DurationLike | string, options?: ArithmeticOptions): Temporal.PlainTime;
+    subtract(durationLike: Temporal.Duration | DurationLike | string, options?: ArithmeticOptions): Temporal.PlainTime;
     until(
       other: Temporal.PlainTime | PlainTimeLike | string,
       options?: DifferenceOptions<'hour' | 'minute' | 'second' | 'millisecond' | 'microsecond' | 'nanosecond'>
@@ -1195,7 +1191,7 @@ export namespace Temporal {
     readonly millisecond: number;
     readonly microsecond: number;
     readonly nanosecond: number;
-    readonly timeZone: Temporal.TimeZone;
+    readonly timeZone: Temporal.TimeZoneProtocol;
     readonly calendar: CalendarProtocol;
     readonly dayOfWeek: number;
     readonly dayOfYear: number;
@@ -1404,7 +1400,7 @@ export namespace Temporal {
   };
 }
 
-declare namespace IntlPolyfill {
+declare namespace Intl {
   type Formattable =
     | Date
     | Temporal.Instant
@@ -1415,11 +1411,11 @@ declare namespace IntlPolyfill {
     | Temporal.PlainYearMonth
     | Temporal.PlainMonthDay;
 
-  interface DateTimeFormatRangePart extends Intl.DateTimeFormatPart {
+  interface DateTimeFormatRangePart extends globalThis.Intl.DateTimeFormatPart {
     source: 'shared' | 'startRange' | 'endRange';
   }
 
-  export interface DateTimeFormat extends Intl.DateTimeFormat {
+  export interface DateTimeFormat extends globalThis.Intl.DateTimeFormat {
     /**
      * Format a date into a string according to the locale and formatting
      * options of this `Intl.DateTimeFormat` object.
@@ -1434,7 +1430,7 @@ declare namespace IntlPolyfill {
      *
      * @param date The date to format.
      */
-    formatToParts(date?: Formattable | number): Intl.DateTimeFormatPart[];
+    formatToParts(date?: Formattable | number): globalThis.Intl.DateTimeFormatPart[];
 
     /**
      * Format a date range in the most concise way based on the locale and
@@ -1459,23 +1455,31 @@ declare namespace IntlPolyfill {
     formatRangeToParts(startDate: Date | number, endDate: Date | number): DateTimeFormatRangePart[];
   }
 
+  export interface DateTimeFormatOptions extends Omit<globalThis.Intl.DateTimeFormatOptions, 'timeZone'> {
+    timeZone?: string | Temporal.TimeZoneProtocol;
+    // TODO: remove the props below after TS lib declarations are updated
+    dayPeriod?: 'narrow' | 'short' | 'long';
+    dateStyle?: 'full' | 'long' | 'medium' | 'short';
+    timeStyle?: 'full' | 'long' | 'medium' | 'short';
+  }
+
   export const DateTimeFormat: {
     /**
      * Creates `Intl.DateTimeFormat` objects that enable language-sensitive
      * date and time formatting.
      */
-    new (locales?: string | string[], options?: Intl.DateTimeFormatOptions): DateTimeFormat;
-    (locales?: string | string[], options?: Intl.DateTimeFormatOptions): DateTimeFormat;
+    new (locales?: string | string[], options?: DateTimeFormatOptions): DateTimeFormat;
+    (locales?: string | string[], options?: DateTimeFormatOptions): DateTimeFormat;
 
     /**
      * Get an array containing those of the provided locales that are supported
      * in date and time formatting without having to fall back to the runtime's
      * default locale.
      */
-    supportedLocalesOf(locales: string | string[], options?: Intl.DateTimeFormatOptions): string[];
+    supportedLocalesOf(locales: string | string[], options?: DateTimeFormatOptions): string[];
   };
 }
 
-export { IntlPolyfill as Intl };
+export { Intl as Intl };
 
 export function toTemporalInstant(this: Date): Temporal.Instant;