add misc helper functions with unit tests

src/puppet-padchat/misc.spec.ts

+#!/usr/bin/env ts-node
+
+// tslint:disable:no-shadowed-variable
+import * as test  from 'blue-tape'
+
+import {
+  isRoomId,
+  isContactId,
+  isOfficialContactId,
+}                       from './misc'
+
+test('isRoomId()', async t => {
+  const ROOM_ID = 'xxx@chatroom'
+  const NOT_ROOM_ID = 'xxxxxxx'
+
+  t.ok(isRoomId(ROOM_ID), 'should return true for ROOM_ID')
+  t.notOk(isRoomId(NOT_ROOM_ID), 'should return false for ROOM_ID')
+})
+
+test('isContactId()', async t => {
+  const CONTACT_ID = 'sxxfdsa'
+  const NOT_CONTACT_ID = 'fdsafasd@chatroom'
+
+  t.ok(isContactId(CONTACT_ID), 'should return true for CONTACT_ID')
+  t.notOk(isContactId(NOT_CONTACT_ID), 'should return false for CONTACT_ID')
+})
+
+test('isOfficialContactId()', async t => {
+  const OFFICIAL_CONTACT_ID = 'gh_sxxfdsa'
+  const NOT_OFFICIAL_CONTACT_ID = 'fdsafasd@chatroom'
+
+  t.ok(isOfficialContactId(OFFICIAL_CONTACT_ID), 'should return true for OFFICIAL_CONTACT_ID')
+  t.notOk(isOfficialContactId(NOT_OFFICIAL_CONTACT_ID), 'should return false for NOT_OFFICIAL_CONTACT_ID')
+})

src/puppet-padchat/misc.ts

+export function isRoomId(id: string) {
+  return /@chatroom$/.test(id)
+}
+
+export function isContactId(id: string) {
+  return !isRoomId(id)
+}
+
+export function isOfficialContactId(id: string) {
+  return /^gh_/i.test(id)
+}