Filter out extraneous items from Timezone.getAvailableTimezones().

Author: kshetline

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@tubular/time",
-  "version": "3.9.5",
+  "version": "3.9.6",
   "description": "Date/time, IANA timezones, leap seconds, TAI/UTC conversions, calendar with settable Julian/Gregorian switchover",
   "main": "dist/cjs/index.js",
   "module": "dist/fesm2015/index.js",

package.json

@@ -54,6 +54,7 @@ describe('Timezone', () => {
     expect(Timezone.from('Europe/Paris').supportsCountry('JA')).to.be.false;
     expect(Array.from(Timezone.from('Pacific/Honolulu').countries).sort().join('')).to.equal('UMUS');
     expect(Timezone.getAvailableTimezones().length).to.be.greaterThan(200);
+    expect(Timezone.getAvailableTimezones().includes('leapSeconds')).to.be.false;
 
     const regions = Timezone.getRegionsAndSubzones();
 
@@ -99,7 +100,7 @@ describe('Timezone', () => {
       'Atlantic/St_Helena', 'Iceland'
     ]);
     expect(Timezone.getAliasesForZone('America/New_York')).to.deep.equal([
-      'EST5EDT', 'SystemV/EST5EDT', 'US/Eastern'
+      'EST5EDT', 'US/Eastern'
     ]);
     expect(Timezone.getAliasesForZone('Antarctica/Mawson')).to.deep.equal([]);
   });

src/timezone.spec.ts

@@ -311,8 +311,10 @@ export class Timezone {
   static getAvailableTimezones(): string[] {
     const zones: string[] = [];
 
-    for (const zone of Object.keys(this.encodedTimezones))
-      zones.push(zone);
+    for (const zone of Object.keys(this.encodedTimezones)) {
+      if (zone.includes('/') || /^[A-Z]/.test(zone)) // Filter out deltaTs, leapSeconds, etc.
+        zones.push(zone);
+    }
 
     zones.sort();