Include Molad details in memo field of MevarchimChodeshEvent

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@hebcal/core",
-  "version": "3.0.4",
+  "version": "3.1.0",
   "author": "Michael J. Radwin (https://github.com/mjradwin)",
   "contributors": [
     "Eyal Schachter (https://github.com/Scimonster)",

src/holidays.js

@@ -19,7 +19,9 @@
     along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 import {Locale} from './locale';
+import {HDate, months} from './hdate';
 import {Event, flags} from './event';
+import {MoladEvent} from './molad';
 
 /** Represents a built-in holiday like Pesach, Purim or Tu BiShvat */
 export class HolidayEvent extends Event {
@@ -116,6 +118,11 @@ export class MevarchimChodeshEvent extends Event {
   constructor(date, monthName) {
     super(date, `${mevarchimChodeshStr} ${monthName}`, flags.SHABBAT_MEVARCHIM);
     this.monthName = monthName;
+    const hyear = date.getFullYear();
+    const hmonth = date.getMonth();
+    const monNext = (hmonth == HDate.monthsInYear(hyear) ? months.NISAN : hmonth + 1);
+    const molad = new MoladEvent(date, hyear, monNext);
+    this.memo = molad.render();
   }
   /**
    * Returns (translated) description of this event

src/holidays.spec.js

@@ -44,6 +44,11 @@ test('basename-and-url', (t) => {
   t.is(mvch.url(), undefined);
 });
 
+test('MevarchimChodeshEvent', (t) => {
+  const mvch = new MevarchimChodeshEvent(new HDate(23, months.KISLEV, 5769), 'Tevet');
+  t.is(mvch.memo, 'Molad Tevet: Sat, 10 minutes and 16 chalakim after 16:00');
+});
+
 test('shushan-purim', (t) => {
   const events = HebrewCalendar.calendar({year: 2015, numYears: 15});
   const shushan = events.filter((ev) => ev.getDesc() == 'Shushan Purim');