How to promisify my Class in nodejs - node.js

Question

I am using bluebird to implementing promisify in my custom lib. I have follwing lib
user, lib-1, lib-2 etc
On user registration, from my user router
// user_router.js
var user = new User();
var lib1 = new Lib1();
var lib2 = new Lib2();
// I am expecting, all method will be async by following 3 lines!
Promise.promisifyAll(user);
Promise.promisifyAll(lib1);
Promise.promisifyAll(lib2);
user.validationAsync(payload)
.then(function(result_from_validation) {
return lib1.validationAsync(payload);
})
.then(function(result_lib1_validation)) {
return lib2.validationAsync(payload)
})
.then(function(result_lib2_validation)) {
// final save
user.registerAsync(payload);
lib1.saveAsync(payload);
lib2.saveAsync(payload);
return {'response-data'}
})
.then(function(response)) {
// send response
res.json('success', 'User successfully created', {});
})
.catch(function(error)) {
//all error will be handled here
//these error will be either throw or by promise rejected.
res.json('error', error.message, {error.stack});
})
In validation method I am throwing errors like
//user_lib.js
// This throw will be handled by router catch. ???
throw Error('Field value is invalid');
In save method mongooes modal also have some validation like user already exist so unable to create user.
function register (payload)
{
// payload data binded on user_modal here
var user_modal = getUserModal(payload);
user_modal.saveAsync()
.then(function(){})
.catch(function(error){
//How to handle error here and send this error to router
})
}
All above is just my expectation. I want to send all response from user_router.js. (My user module already implemented. now need to integrate it by bluebird)
Now Question ::
How can I do it by bluebird ? How to set resolve/reject method on
user object(explicitly) ??
If validation method throw error then it
will be captured by router catch method ???
How can I send any
error/rejection to router's catch from mongooes (see user register
method)?
I hope you will get my points. Thanks in advance!!
You can also share any example link to implement these things.

Answer 1

Now I am using try catch for normal statement and using promise for async error handling!! :) Thanks a lot guyz