Add some additional TypeScript readonly keywords

src/YomKippurKatanEvent.ts

@@ -3,7 +3,7 @@ import {flags} from './event';
 import {HolidayEvent} from './HolidayEvent';
 import './locale'; // Adds Hebrew and Ashkenazic translations
 
-export const ykk = 'Yom Kippur Katan';
+const ykk = 'Yom Kippur Katan';
 
 /** YKK is minor day of atonement on the day preceeding each Rosh Chodesh */
 export class YomKippurKatanEvent extends HolidayEvent {

src/hebcal.ts

@@ -578,7 +578,7 @@ export class HebrewCalendar {
           isSaturday
         );
         if (isFriday && candlesEv && sedra) {
-          const parsha = sedra!.lookup(abs);
+          const parsha = sedra.lookup(abs);
           const pe = new ParshaEvent(hd.next(), parsha.parsha, il, parsha.num);
           candlesEv.memo = pe.render(options.locale);
         }

src/sedra.ts

@@ -82,7 +82,7 @@ export class Sedra {
   private readonly year: number;
   private readonly il: boolean;
   private readonly firstSaturday: number;
-  private readonly theSedraArray: NumberOrString[];
+  private readonly theSedraArray: readonly NumberOrString[];
   /**
    * Caculates the Parashah HaShavua for an entire Hebrew year
    * @param hyear - Hebrew year (e.g. 5749)
@@ -262,7 +262,7 @@ export class Sedra {
    * Returns the underlying annual sedra schedule.
    * Used by `@hebcal/triennial`
    */
-  getSedraArray(): NumberOrString[] {
+  getSedraArray(): readonly NumberOrString[] {
     return this.theSedraArray;
   }
 
@@ -324,7 +324,7 @@ export class Sedra {
  * @readonly
  * @type {string[]}
  */
-export const parshiot: string[] = [
+export const parshiot: readonly string[] = [
   'Bereshit',
   'Noach',
   'Lech-Lecha',
@@ -378,7 +378,7 @@ export const parshiot: string[] = [
   'Nitzavim',
   'Vayeilech',
   "Ha'azinu",
-];
+] as const;
 
 // 0-based parsha IDs
 const parsha2id = new Map<string, number>();
@@ -435,15 +435,15 @@ const SHAVUOT = 'Shavuot'; // 33
  * @param start beginning number, inclusive
  * @param stop ending number, inclusive
  */
-function range(start: number, stop: number): number[] {
+function range(start: number, stop: number): readonly number[] {
   return Array.from({length: stop - start + 1}, (v, k) => k + start);
 }
 
 type NumberOrString = number | string;
 
-const yearStartVayeilech: NumberOrString[] = [51, 52, CHMSUKOT];
-const yearStartHaazinu: NumberOrString[] = [52, YK, CHMSUKOT];
-const yearStartRH: NumberOrString[] = [RH, 52, SUKKOT, SHMINI];
+const yearStartVayeilech: readonly NumberOrString[] = [51, 52, CHMSUKOT];
+const yearStartHaazinu: readonly NumberOrString[] = [52, YK, CHMSUKOT];
+const yearStartRH: readonly NumberOrString[] = [RH, 52, SUKKOT, SHMINI];
 const r020 = range(0, 20);
 const r027 = range(0, 27);
 const r3340 = range(33, 40);
@@ -456,7 +456,7 @@ const r4350 = range(43, 50);
  * @private
  * @readonly
  */
-const types: {[s: string]: NumberOrString[]} = {
+const types: {[s: string]: readonly NumberOrString[]} = {
   /* Hebrew year that starts on Monday, is `incomplete' (Heshvan and
    * Kislev each have 29 days), and has Passover start on Tuesday. */
   // e.g. 5753

src/tachanun.ts

@@ -1,7 +1,7 @@
 import {HDate, months} from '@hebcal/hdate';
 import {dateYomHaZikaron} from './modern';
 
-function range(start: number, end: number): number[] {
+function range(start: number, end: number): readonly number[] {
   const arr = [];
   for (let i = start; i <= end; i++) {
     arr.push(i);
@@ -67,7 +67,13 @@ function tachanun0(
   return ret;
 }
 
-function tachanunYear(year: number, il: boolean): any {
+type TachanunYear = {
+  none: number[];
+  some: number[];
+  yesPrev: number[];
+};
+
+function tachanunYear(year: number, il: boolean): TachanunYear {
   const leap = HDate.isLeapYear(year);
   const monthsInYear = HDate.monthsInYear(year);
   let av9dt = new HDate(9, months.AV, year);
@@ -78,7 +84,7 @@ function tachanunYear(year: number, il: boolean): any {
   if (shushPurim.getDay() === 6) {
     shushPurim = shushPurim.next();
   }
-  const none: HDate[] = [
+  const none: readonly HDate[] = [
     new HDate(2, months.TISHREI, year), // Rosh Hashana II
   ].concat(
     // Rosh Chodesh - 1st of every month. Also includes RH day 1 (1 Tishrei)
@@ -108,7 +114,7 @@ function tachanunYear(year: number, il: boolean): any {
     shushPurim,
     leap ? new HDate(14, months.ADAR_I, year) : [] // Purim Katan
   );
-  const some: HDate[] = [
+  const some: readonly HDate[] = [
     new HDate(14, months.IYYAR, year), // Pesach Sheini
   ].concat(
     // Until 14 Sivan
@@ -120,7 +126,7 @@ function tachanunYear(year: number, il: boolean): any {
     // Yom Yerushalayim
     year >= 5727 ? new HDate(28, months.IYYAR, year) : []
   );
-  const yesPrev: HDate[] = [
+  const yesPrev: readonly HDate[] = [
     new HDate(29, months.ELUL, year - 1), // Erev Rosh Hashanah
     new HDate(9, months.TISHREI, year), // Erev Yom Kippur
     new HDate(14, months.IYYAR, year), // Pesach Sheini