.eslintrc.json

// see also: https://eslint.org/docs/user-guide/configuring
{
  "ignorePatterns": ["/lib/"],

  // config common to all
  "env": {
    "es6": true,
    "es2017": true,
    "node": true
  },
  "parserOptions": {
    "ecmaVersion": 2019,
    "sourceType": "module"
  },

  "overrides": [
    // all files to be preformatted
    {
      "files": ["**/*.js", "lib/**/*.d.ts"],
      "rules": {
        "lines-around-comment": [
          "error",
          {
            "beforeBlockComment": true,
            "beforeLineComment": true,
            "allowBlockStart": true,
            "allowObjectStart": true,
            "allowArrayStart": true,
            "allowClassStart": true
          }
        ]
      }
    },

    // all TypeScript files
    {
      "files": ["**/*.ts"],
      "plugins": ["@typescript-eslint"],
      "parser": "@typescript-eslint/parser"
    },

    // basic rules
    {
      "files": ["src/**/*.ts"],
      "extends": ["eslint:recommended", "prettier"]
    },

    // rules for source code in TypeScript
    {
      "files": ["src/**/*.ts"],
      "parserOptions": { "project": "tsconfig.json" },
      "plugins": ["total-functions"],
      "extends": [
        "plugin:@typescript-eslint/recommended",
        "plugin:@typescript-eslint/recommended-requiring-type-checking",
        "plugin:total-functions/recommended",
        "prettier"
      ],
      "rules": {
        "no-fallthrough": "off" // already checked by TypeScript
      }
    }
  ]
}