.eslintrc.json

{
  "extends": "./.eslintrc-no-types.json",
  "overrides": [
    {
      "files": ["./config/*.ts", "./data/**/*.ts", "./lib/*.ts", "./server/**/*.ts", "./sim/**/*.ts", "./tools/set-import/*.ts"],
      "parser": "@typescript-eslint/parser",
      "parserOptions": {
        "ecmaVersion": 9,
        "sourceType": "module",
        "tsconfigRootDir": ".",
        "project": ["./tsconfig.json"]
      },
      "extends": [
        "plugin:@typescript-eslint/recommended",
        "plugin:@typescript-eslint/recommended-requiring-type-checking",
        "./.eslintrc-no-types.json"
      ],
      "rules": {
        // TODO investigate
        "@typescript-eslint/restrict-plus-operands": "off",
        // "@typescript-eslint/restrict-plus-operands": ["error", {"checkCompoundAssignments": true}],
        // "@typescript-eslint/switch-exhaustiveness-check": "error",

        // typescript-eslint defaults too strict
        "@typescript-eslint/no-unsafe-assignment": "off",
        "@typescript-eslint/no-unsafe-call": "off",
        "@typescript-eslint/no-unsafe-member-access": "off",
        "@typescript-eslint/no-unsafe-return": "off",
        "@typescript-eslint/restrict-template-expressions": "off",

        // probably bugs
        "@typescript-eslint/no-floating-promises": "error",
        "@typescript-eslint/no-for-in-array": "error",
        "@typescript-eslint/no-misused-promises": "error",
        "@typescript-eslint/no-throw-literal": "error",
        "@typescript-eslint/no-unnecessary-condition": "off", // sadly, we use not-null assertions so commonly that these are often necessary

        // syntax style (local syntactical, usually autofixable formatting decisions)
        "@typescript-eslint/no-unnecessary-qualifier": "off",
        "@typescript-eslint/no-unnecessary-type-arguments": "error",
        "@typescript-eslint/no-unnecessary-type-assertion": "error",
        "@typescript-eslint/prefer-regexp-exec": "error",
        "@typescript-eslint/prefer-string-starts-ends-with": "error"
      }
    }
  ]
}