使用以下命令启动Firebase项目模拟器（使用云函数和FireStore）

firebase emulators:start

它运行成功，并给我一个路径连接到功能，并显示了一个本地主机的网址firestore太。
然后，为了执行我的jest测试，运行下面的命令

firebase emulators:exec --only firestore jest

根据文档，要连接到本地firstore，我们需要使用exec。但它的错误之下抛出。

i  emulators: Starting emulators: firestore
⚠  emulators: emulator hub unable to start on port 4400, starting on 4401
✔  hub: emulator hub started at http://localhost:4401
i  Shutting down emulators.
i  Stoppping emulator hub
⚠  Port 8080 is not open on localhost, could not start firestore emulator.
i  To select a different host/port for the emulator, update your "firebase.json":
    {
      // ...
      "emulators": {
        "firestore": {
          "host": "HOST",
          "port": "PORT"
        }
      }
    }
i  Shutting down emulators.
Error: Could not start firestore emulator, port taken.

每次运行exec命令时都会抛出此错误。有人能指出可能出了什么问题吗？
编辑：来自firebase模拟器的日志：start

firebase emulators:start
i  emulators: Starting emulators: functions, firestore, hosting, pubsub
✔  hub: emulator hub started at http://localhost:4400
⚠  Your requested "node" version "8" doesn't match your global version "10"
✔  functions: functions emulator started at http://localhost:5001
i  firestore: Serving ALL traffic (including WebChannel) on http://localhost:8080
⚠  firestore: Support for WebChannel on a separate port (8081) is DEPRECATED and will go away soon. Please use port above instead.
i  firestore: firestore emulator logging to firestore-debug.log
✔  firestore: firestore emulator started at http://localhost:8080
i  firestore: For testing set FIRESTORE_EMULATOR_HOST=localhost:8080
i  hosting[website]: Serving hosting files from: public
✔  hosting[website]: Local server: http://localhost:5000
i  hosting[admin]: Serving hosting files from: public
✔  hosting[admin]: Local server: http://localhost:5005
i  hosting[b2b]: Serving hosting files from: public
✔  hosting[b2b]: Local server: http://localhost:5006
i  hosting[b2c]: Serving hosting files from: public
✔  hosting[b2c]: Local server: http://localhost:5007
i  hosting[sdk]: Serving hosting files from: public
✔  hosting[sdk]: Local server: http://localhost:5008
✔  hosting: hosting emulator started at http://localhost:5000
i  pubsub: pubsub emulator logging to pubsub-debug.log
✔  pubsub: pubsub emulator started at http://localhost:8085

更新

重新启动时，也会显示上述错误。但关闭端口让它工作。
在package.json的scipts部分添加

"kill": "npx kill-port 5000 5001 8080 8085 4000 9229"

然后逃跑

npm run kill

此处不需要上述所有端口。只是8080可能在你的情况下工作，但我有其他端口也被模拟器使用。