.eslintrc.json

{
    "env": {
        "browser": true
    },
    "parser": "@typescript-eslint/parser",
    "parserOptions": {
        "ecmaVersion": 12,
        "sourceType": "module",
        "project": "./tsconfig.json"
    },

    "overrides": [
        {
            "files": ["*.js"],
            "extends": ["eslint:recommended",
                        "google"],
            "rules": {
                "max-len": ["error", { "code": 120 }],
                "indent": ["error", 4]
            }
        },
        {
            "files": ["*.ts"],
            "plugins": [
                "@typescript-eslint"
            ],
            "extends": ["plugin:@typescript-eslint/eslint-recommended",
                        "plugin:@typescript-eslint/recommended",
                        "airbnb-typescript/base"],
            "rules": {
                "max-len": ["error", { "code": 120 }],
                "indent": "off",
                "semi": [2, "always"],
                "quotes": ["error", "single"],
                "no-console": 2,
                "newline-per-chained-call": "off",
                "max-classes-per-file": ["error", 2],
                "@typescript-eslint/indent": ["error", 4],
                "no-case-declarations": "off",
                "class-methods-use-this": "off",
                "@typescript-eslint/explicit-function-return-type": 2,
                "@typescript-eslint/prefer-optional-chain": 2,
                "@typescript-eslint/consistent-type-imports": 2,
                "@typescript-eslint/no-confusing-non-null-assertion": 2,
                "@typescript-eslint/no-duplicate-imports": 2,
                "@typescript-eslint/no-redeclare": 2,
                "@typescript-eslint/no-shadow": 2
            }
        }
    ]
}