In ' "db": "json-server -w db.json -p 3001" ', what is '-w' in here means?

what is -w in here means ?

"db": "json-server -w db.json -p 3001"

this is the package .json file

{
  "name": "jsonserver",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "db": "json-server -w db.json -p 3001",
    "tunnel": "ngrok http 3001"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "axios": "^0.24.0",
    "json-server": "^0.17.0",
    "ngrok": "^4.2.2"
  }
}

and i am doing this for a react-native project what does -w means?