Async Callbacks with Express

async-express.js

"use strict";

const express = require('express');
const app = express();
const port = 3000;

function asyncHandler(fn) {
    return function(req, res, next) {
        Promise
            .resolve(fn(req, res, next))
            .catch(next);
    }

}

function asyncErrorHandler(fn) {
    return function(err, req, res, next) {
        Promise
            .resolve(fn(err, req, res, next))
            .catch(next);
    }
}

app.get('/test', asyncHandler(async (req, res) => {
    await new Promise(resolve => {
        resolve();
    });

    res.send({
        message: 'G!'
    });
}));

app.get('/error', asyncHandler(async (req, res) => {
    await new Promise((resolve, reject) => {
        reject(new Error('NG!'));
    });
}));

app.use(asyncErrorHandler(async function(err, req, res, next) {
    res.send({
        error: err.message
    });
}));

app.listen(port, () => console.log('Ready for Work!'));