#291 change `throw error` to `return null` (#292)

* #291 change throw error to return null

* add jsDoc

src/contact.ts

@@ -348,14 +348,16 @@ export class Contact implements Sayable {
   }
 
   /**
-   * try to find a contact by filter: {name: string | RegExp}
+   * try to find a contact by filter: {name: string | RegExp} / {alias: string | RegExp}
+   * @param {ContactQueryFilter} query
+   * @returns {Promise<Contact | null>} If can find the contact, return Contact, or return null
    */
-  public static async find(query: ContactQueryFilter): Promise<Contact> {
+  public static async find(query: ContactQueryFilter): Promise<Contact | null> {
     log.verbose('Contact', 'find(%s)', JSON.stringify(query))
 
     const contactList = await Contact.findAll(query)
     if (!contactList || !contactList.length) {
-      throw new Error('find not found any contact')
+      return null
     }
 
     if (contactList.length > 1) {

src/room.ts

@@ -498,12 +498,17 @@ export class Room extends EventEmitter implements Sayable {
                   })
   }
 
-  public static async find(query: RoomQueryFilter): Promise<Room> {
+  /**
+   * try to find a room by filter: {topic: string | RegExp}
+   * @param {RoomQueryFilter} query
+   * @returns {Promise<Room | null>} If can find the room, return Room, or return null
+   */
+  public static async find(query: RoomQueryFilter): Promise<Room | null> {
     log.verbose('Room', 'find({ topic: %s })', query.topic)
 
     const roomList = await Room.findAll(query)
     if (!roomList || roomList.length < 1) {
-      throw new Error('no room found')
+      return null
     }
     const room = roomList[0]
     await room.ready()