ESLint 不通知某些错误？

Question

I'm trying to set up a React app with Gatsby, and for some reason the ESLint doesn't seem to be fully working properly.

I put the code const test = 4; and left the variable unused, which I would expect to throw an unused-variable error in ESLint, but it does not.

I use VSCode.

This is my eslintrc.json

{
  "extends": ["airbnb", "prettier", "prettier/react"],
  "plugins": ["prettier"],
  "rules": {
    "prettier/prettier": "error"
  }
}

These are the dependencies in my package.json

    "dependencies": {
    "@material-ui/core": "^4.11.0",
    "@material-ui/icons": "^4.9.1",
    "gatsby": "^2.24.67",
    "gatsby-cli": "^2.12.102",
    "gatsby-plugin-material-ui": "^2.1.10",
    "react": "^16.12.0",
    "react-dom": "^16.12.0"
  },
  "devDependencies": {
    "eslint": "^7.10.0",
    "eslint-config-airbnb": "^18.2.0",
    "eslint-config-prettier": "^6.12.0",
    "eslint-plugin-prettier": "^3.1.4",
    "prettier": "2.0.5"
  },

Answer 1

You need to add the rule in your eslintrc.json file:

"rules":{
    "no-unused-vars": "warn",
}

Of course, you can change the warning for your desired behavior. You can check for further details in ESLint docs .