move SayableMessage to plugin-contrib

src/mod.ts

@@ -67,7 +67,3 @@ export { IoClient }   from './io-client'
 export {
   Sayable,
 }                   from './types'
-export {
-  SayableMessage,
-  toSayableMessage,
-}                     from './sayable-message'

src/sayable-message.ts

-import {
-  FileBox,
-  Message,
-  Contact,
-  UrlLink,
-  MiniProgram,
-  log,
-}                 from './mod'
-
-export type SayableMessage =  undefined
-                            | Message
-                            | string
-                            | FileBox
-                            | Contact
-                            | UrlLink
-                            | MiniProgram
-
-async function toSayableMessage (message: Message): Promise<SayableMessage> {
-  const type = message.type()
-  switch (type) {
-    case Message.Type.Text:
-      return message.text()
-    case Message.Type.Image:
-    case Message.Type.Attachment:
-    case Message.Type.Audio:
-    case Message.Type.Video:
-    case Message.Type.Emoticon:
-      return message.toFileBox()
-    case Message.Type.Contact:
-      return message.toContact()
-    case Message.Type.Url:
-      return message.toUrlLink()
-    case Message.Type.MiniProgram:
-      return message.toMiniProgram()
-
-    default:
-      log.silly('Wechaty', 'toSayableMessage(%s) non-convertible type: %s', message, type)
-      return undefined
-  }
-}
-
-export {
-  toSayableMessage,
-}