javascript - Is there a way to wrap an await/async try/catch block to every function?

Question

So i'm using express.js and looking into using async/await with node 7. Is there a way that I can still catch errors but get rid of the try/catch block? Perhaps a function wrapper? I'm not sure how this would actually execute the function's code and also call next(err).

exports.index = async function(req, res, next) {
  try {
    let user = await User.findOne().exec();

    res.status(200).json(user);
  } catch(err) {
    next(err);
  }
}

Something like this...?

function example() {
   // Implements try/catch block and then handles error.
}

exports.index = async example(req, res, next) {
  let user = await User.findOne().exec();
  res.status(200).json(user);
}

EDIT:

Something more similar to this:

var wrapper = function(f) {
    return function() {
        try {
            f.apply(this, arguments);
        } catch(e) {
            customErrorHandler(e)
        }
    }
}

This would somehow handle the try/catch block but doesn't work:

exports.index = wrapper(async example(req, res, next) {
  let user = await User.findOne().exec();
  res.status(200).json(user);
});

See Is there a way to add try-catch to every function in Javascript? for the non-async example.

Answer 1

Yes, you can easily write such a wrapper for asynchronous functions as well - just use async/await:

function wrapper(f) {
    return async function() {
//         ^^^^^
        try {
            return await f.apply(this, arguments);
//                 ^^^^^
        } catch(e) {
            customErrorHandler(e)
        }
    }
}

Or you use promises directly, like in this example that is more tailored to express (especially with the number of parameters):

function promiseWrapper(fn) {
    return (req, res, next) => {
         fn(req, res).catch(next);
    };
}