.eslintrc

{
  "parser": "@typescript-eslint/parser",
  "plugins": ["@typescript-eslint"],
  "env": {
    "browser": true,
    "es6": true,
    "node": true
  },
  "parserOptions": {
    "ecmaVersion": 2018,
    "sourceType": "module"
  },
  "rules": {
    // see https://github.com/airbnb/javascript/blob/master/packages/eslint-config-airbnb-base/rules/style.js#L122
    "indent": [
      2,
      2,
      {
        "SwitchCase": 1,
        "VariableDeclarator": 1,
        "outerIIFEBody": 1,
        "FunctionDeclaration": {
          "parameters": 1,
          "body": 1
        },
        "FunctionExpression": {
          "parameters": 1,
          "body": 1
        },
        "CallExpression": {
          "arguments": 1
        },
        "ArrayExpression": 1,
        "ObjectExpression": 1,
        "ImportDeclaration": 1,
        "flatTernaryExpressions": false,
        "ignoreComments": false
      }
    ],

    "semi": [2, "never"],
    "semi-spacing": [2, { "before": false, "after": true }],
    "wrap-iife": [2, "inside"],
    "no-use-before-define": [2, { "functions": true, "classes": true, "variables": true }],
    "no-caller": 2,
    "no-cond-assign": [2, "except-parens"],
    "no-constant-condition": 2,
    "no-debugger": 2,
    "no-dupe-args": 2,
    "no-dupe-keys": 2,
    "no-duplicate-case": 2,
    "no-empty": [2, { "allowEmptyCatch": true }],
    "no-extra-boolean-cast": 2,
    "no-extra-semi": 2,
    "no-func-assign": 2,
    "no-new": 2,
    "no-sparse-arrays": 2,
    "no-undef": 2,
    "no-unexpected-multiline": 2,
    "no-unreachable": 2,
    "no-unused-vars": [
      2,
      {
        "args": "after-used",
        "argsIgnorePattern": "^_",
        "ignoreRestSiblings": true,
        "vars": "all",
        "varsIgnorePattern": "^_"
      }
    ],

    "strict": 2,
    "max-params": [2, 5],
    "max-depth": [1, 4],
    "no-eq-null": 0,
    "no-unused-expressions": 0,
    "dot-notation": 2,
    "use-isnan": 2,

    // Best practices
    "block-scoped-var": 2,
    "complexity": [0, 11],
    "curly": [2, "multi-line"],
    "eqeqeq": [2, "always", { "null": "ignore" }],
    "no-else-return": 2,
    "no-extra-bind": 2,
    "no-implicit-coercion": 2,
    "no-return-assign": 0,
    "no-sequences": 2,
    "yoda": 2,

    // Variables
    "no-var": 1,

    // Codestyle
    "arrow-parens": [2, "always"],
    "array-bracket-spacing": [2, "never"],
    "brace-style": [2, "1tbs", { "allowSingleLine": true }],
    "camelcase": [2, { "properties": "never" }],
    "comma-dangle": ["warn", "always-multiline"],
    "comma-spacing": [2, { "before": false, "after": true }],
    "eol-last": 2,
    "func-call-spacing": [2, "never"],
    "block-spacing": 2,
    "keyword-spacing": [2, { "before": true, "after": true }],
    "max-len": [
      2,
      {
        "code": 100,
        "ignoreUrls": true,
        "ignoreComments": false,
        "ignoreRegExpLiterals": true,
        "ignoreStrings": true,
        "ignoreTemplateLiterals": true,
        "ignorePattern": "require"
      }
    ],
    "no-lonely-if": 2,
    "no-mixed-spaces-and-tabs": 2,
    "no-multi-spaces": 2,
    "no-multiple-empty-lines": [2, { "max": 1, "maxBOF": 0, "maxEOF": 0 }],
    "no-trailing-spaces": 2,
    "no-unneeded-ternary": 2,
    "no-nested-ternary": 2,
    "object-curly-spacing": [2, "always"],
    "one-var-declaration-per-line": [2, "initializations"],
    "one-var": [2, { "let": "never", "const": "never" }],
    "padded-blocks": [2, "never"],
    "quote-props": [2, "as-needed", { "numbers": true }],
    "quotes": [2, "single", { "avoidEscape": true }],
    "space-before-blocks": [2, "always"],
    "space-before-function-paren": [
      2,
      {
        "asyncArrow": "always",
        "anonymous": "never",
        "named": "never"
      }
    ],
    "space-in-parens": 2,
    "key-spacing": [2, { "beforeColon": false, "afterColon": true, "mode": "strict" }],
    "space-infix-ops": 2,

    // https://github.com/typescript-eslint/typescript-eslint/tree/master/packages/eslint-plugin#supported-rules
    "@typescript-eslint/consistent-type-assertions": 2,
    "@typescript-eslint/no-empty-interface": 2,
    "@typescript-eslint/no-unused-vars": [
      2,
      {
        "args": "after-used",
        "argsIgnorePattern": "^_",
        "ignoreRestSiblings": true,
        "vars": "all",
        "varsIgnorePattern": "^_"
      }
    ]
  },
  "overrides": [
    {
      "files": ["*.test.ts"],
      "env": {
        "jest": true
      }
    },
    {
      "files": ["*.js"],
      "rules": {
        "strict": 0
      }
    }
  ]
}