How to show warnings instead of errors on all ESLint rules with React?

To show warnings instead of errors on all ESLint rules with React, we set each rule to 'warm' in .eslintrc.

For instance, we write

{
  "rules": {
    //...
    "prettier/prettier": "warn"
  }
}

to set "prettier/prettier" to "warn' in "rules' to make ESLint return a warning instead of an error when the rule is violated.