asyncMiddleware.js

const asyncHandler = fn => (req, res, next) =>
    Promise
        .resolve(fn(req, res, next))
        .catch(next);

module.exports = asyncHandler;

// Implementation (Controller method)
exports.someRoute = asyncHandler(async (req, res, next) => {
    const foo = await Bar.find();

    res.status(200).json({bar});
});