better event listener overloading

src/room.ts

@@ -10,7 +10,10 @@
  */
 import { EventEmitter } from 'events'
 
-import Config     from './config'
+import {
+    Config
+  , Sayable
+}                 from './config'
 import Contact    from './contact'
 import Message    from './message'
 import UtilLib    from './util-lib'
@@ -39,6 +42,9 @@ export type RoomRawObj = {
   MemberList:       RoomRawMemberList[]
 }
 
+export type RoomEventName = 'join' | 'leave' | 'topic'
+                          | 'EVENT_PARAM_ERROR'
+
 export type RoomQueryFilter = {
   topic: string | RegExp
 }
@@ -101,12 +107,13 @@ export class Room extends EventEmitter {
     })
   }
 
-  public on(event: 'leave', listener: (leaver: Contact) => void): this
+  public on(event: 'leave', listener: (this: Sayable, leaver: Contact) => void): this
   public on(event: 'join' , listener: (invitee:      Contact   , inviter: Contact)  => void): this
   public on(event: 'join' , listener: (inviteeList:  Contact[] , inviter: Contact)  => void): this
   public on(event: 'topic', listener: (topic: string, oldTopic: string, changer: Contact) => void): this
+  public on(event: 'EVENT_PARAM_ERROR', listener: () => void): this
 
-  public on(event: string, listener: Function): this {
+  public on(event: RoomEventName, listener: Function): this {
     log.verbose('Room', 'on(%s, %s)', event, typeof listener)
 
     const thisWithSay = {

src/wechaty.ts

@@ -17,7 +17,6 @@ import {
   , HeadType
   , PuppetType
   , Sayable
-  , WechatyEventName
 }                     from './config'
 
 import Contact        from './contact'
@@ -27,7 +26,6 @@ import Puppet         from './puppet'
 import PuppetWeb      from './puppet-web/'
 import Room           from './room'
 import UtilLib        from './util-lib'
-// import EventScope     from './event-scope'
 
 import log            from './brolog-env'
 
@@ -38,6 +36,18 @@ export type WechatySetting = {
   // port?:       number
 }
 
+type WechatyEventName = 'error'
+                      | 'friend'
+                      | 'heartbeat'
+                      | 'login'
+                      | 'logout'
+                      | 'message'
+                      | 'room-join'
+                      | 'room-leave'
+                      | 'room-topic'
+                      | 'scan'
+                      | 'EVENT_PARAM_ERROR'
+
 export class Wechaty extends EventEmitter {
   private static _instance: Wechaty
 
@@ -157,12 +167,13 @@ export class Wechaty extends EventEmitter {
   public on(event: 'heartbeat'  , listener: (this: Sayable, data: any) => void): this
   public on(event: 'logout'     , listener: (this: Sayable, user: Contact) => void): this
   public on(event: 'login'      , listener: (this: Sayable, user: Contact) => void): this
-  public on(event: 'message'    , listener: (this: Sayable, message: Message, n: number) => void): this
-  public on(event: 'room-join'  , listener: (this: Sayable, room: Room, invitee:     Contact, inviter: Contact) => void): this
-  public on(event: 'room-join'  , listener: (this: Sayable, room: Room, inviteeList: Contact, inviter: Contact) => void): this
+  public on(event: 'message'    , listener: (this: Sayable, message: Message) => void): this
+  public on(event: 'room-join'  , listener: (this: Sayable, room: Room, invitee:      Contact,    inviter: Contact) => void): this
+  public on(event: 'room-join'  , listener: (this: Sayable, room: Room, inviteeList:  Contact[],  inviter: Contact) => void): this
   public on(event: 'room-leave' , listener: (this: Sayable, room: Room, leaver: Contact) => void): this
   public on(event: 'room-topic' , listener: (this: Sayable, room: Room, topic: string, oldTopic: string, changer: Contact) => void): this
   public on(event: 'scan'       , listener: (this: Sayable, url: string, code: number) => void): this
+  public on(event: 'EVENT_PARAM_ERROR', listener: () => void): this
 
   public on(event: WechatyEventName, listener: Function): this {
     log.verbose('Wechaty', 'on(%s, %s)', event, typeof listener)