fix typing, and all unit tests are PASSED! :D

src/puppet-mock/puppet-mock.ts

@@ -89,6 +89,8 @@ export class PuppetMock extends Puppet {
       type      : MessageType.Text,
       text      : 'mock text',
       timestamp : Date.now(),
+      fromId    : 'xxx',
+      toId      : 'xxx',
     })
 
     setInterval(() => {

src/puppet-puppeteer/puppet-puppeteer.ts

@@ -365,17 +365,33 @@ export class PuppetPuppeteer extends Puppet {
 
     const type: MessageType = this.messageTypeFromWeb(rawPayload.MsgType)
 
-    const payload: MessagePayload = {
+    const payloadBase = {
       id,
       type,
       fromId,
       filename,
-      toId,
-      roomId,
       text,
       timestamp,
     }
 
+    let payload: MessagePayload
+
+    if (toId) {
+      payload = {
+        ...payloadBase,
+        toId,
+        roomId,
+      }
+    } else if (roomId) {
+      payload = {
+        ...payloadBase,
+        toId,
+        roomId,
+      }
+    } else {
+      throw new Error('neither roomId nor toId')
+    }
+
     return payload
   }
 

src/puppet-puppeteer/puppeteer-message.spec.ts

@@ -89,6 +89,7 @@ test('constructor()', async t => {
       type      : Message.Type.Text,
       fromId    : EXPECTED.from,
       timestamp : Date.now(),
+      toId      : 'toId',
     }
     return payload
   })

src/puppet/schemas/message.ts

@@ -8,15 +8,25 @@ export enum MessageType {
   Video,
 }
 
-export interface MessagePayload {
+export interface MessagePayloadBase {
   id : string,
 
   type : MessageType,
 
   filename? : string,
-  fromId?   : string,
-  roomId?   : null | string,
+  fromId    : string,
   text?     : string,
   timestamp : number,   // milliseconds
+}
+
+export interface MessagePayloadRoom {
+  roomId : null | string,
   toId?  : null | string,   // if to is not set, then room must be set
 }
+
+export interface MessagePayloadTo {
+  roomId?   : null | string,
+  toId     : null | string,   // if to is not set, then room must be set
+}
+
+export type MessagePayload = MessagePayloadBase & (MessagePayloadRoom | MessagePayloadTo)