throw error on screen in nodejs code example

Example 1: node js throw error

FactoryController.prototype.create = function (callback) {
    //The throw is working, and the exception is returned.
    throw new Error('An error occurred'); //outside callback 
    try {
        this.check(function (check_result) {
            callback(check_result);
        });
    } catch (ex) {
        throw new Error(ex.toString());
    }
}

FactoryController.prototype.create = function (callback) {
    try {
        this.check(function (check_result) {
            //The throw is not working on this case to return the exception to the caller(parent)
            throw new Error('An error occurred'); //inside callback 
        });
    } catch (ex) {
        throw new Error(ex.toString());
    }
}

Example 2: error handling in node js

app.get('/', function (req, res, next) {
  Promise.resolve().then(function () {
    throw new Error('BROKEN')
  }).catch(next) // Errors will be passed to Express.
})