{
    "env": {
        "browser": true,
        "node": false
    },

    "rules": {
        // Strict mode
        "strict": ["error", "function"], // "global" in Node, "function" in a browser

        // Stylistic issues
        "id-blacklist": ["error", "event"],

        // ECMAScript 6
        "no-var": "off",
        "object-shorthand": "off",
        "prefer-arrow-callback": "off",
        "prefer-const": "off",
        "prefer-rest-params": "off",
        "prefer-spread": "off",
        "prefer-template": "off"
    },

    "globals": {
        "jQuery": false
    }
}

{
    "parserOptions": {
        "ecmaVersion": 5
    },

    "env": {
        "es6": false,
        "browser": true,
        "node": false
    },

    "rules": {
        // Strict mode
        "strict": ["error", "function"], // "global" in Node, "function" in a browser

        // Stylistic issues
        "id-blacklist": ["error", "event"],

        // ECMAScript 6
        "no-var": "off",
        "object-shorthand": "off",
        "prefer-arrow-callback": "off",
        "prefer-const": "off",
        "prefer-rest-params": "off",
        "prefer-spread": "off",
        "prefer-template": "off"
    },

    "globals": {
        "jQuery": false
    }
}

Switch the parser mode in src/ to ES5
ESLint: Switch the parser mode in src/ to ES5
