ESLint extends vs plugins v2020

Question

There's answered question which in my opinion doesn't actually answers the question, on the difference between extends: [] vs plugins: [] in ESLint.

In my case, i just used extends section:

extends: [
  'plugin:@typescript-eslint/recommended',
],
plugins: [],
rules: {
  '@typescript-eslint/explicit-function-return-type': [
    'error',
    {
      allowExpressions: true,
    },
  ],
}

As you can see, i just used predefined config from plugin:@typescript-eslint/recommended and also overwritten @typescript-eslint/explicit-function-return-type rule in rules: {} section. But why do we need this PLUGINS section then? If everything works without it? What do i miss?

Answer 1

You have done it correctly.

For your example, there are 2 ways to do add typescript-eslint...

• 1st way:

{
  parser: "@typescript-eslint/parser",
  parserOptions: { sourceType: "module" },
  plugins: ["@typescript-eslint"],
  extends: [],
  rules: {
    "@typescript-eslint/explicit-function-return-type": [
      "error",
      {
        allowExpressions: true
      }
    ]
  }
}

• 2nd way:

{
  plugins: [],
  extends: ["plugin:@typescript-eslint/recommended"],
  rules: {
    "@typescript-eslint/explicit-function-return-type": [
      "error",
      {
        allowExpressions: true
      }
    ]
  }
}

The difference is...

• 1st way:
  • parser, parserOptions and plugins are manually added,
  • Only @typescript-eslint/explicit-function-return-type is enforced.
• 2nd way:
  • plugin:@typescript-eslint/recommended has automatically added parser, parserOptions and plugins.
  • Recommended typescript rules are added and enforced.
  • @typescript-eslint/explicit-function-return-type is augmented and enforced.

This is why when you use plugin:@typescript-eslint/recommended, things work normally even if plugins is empty. A well-written plugins/configs allows that to happen.