I am developing an API that I would to return a promise. The returned promise is composed of several other promises, so I'm using Q.all and/or Q.allSettled. The problem I'm running into is that the code never completes (see test).
I'm expecting to be able to call then/fail/etc on what's being return from addUsers, which is a Q.all or Q.allSettlted
API:
'use strict';
var Q = require('q'),
mongoose = require('mongoose'),
User = require('../models/user'),
_ = require('underscore');
var addUsers = function (users) {
var promises = _.map(users, function (user) {
var newUser = new User(user);
var promise = Q.nbind(newUser.save, newUser);
return promise();
});
return Q.allSettled(promises);
};
module.exports.addUsers = addUsers;
Test:
'use strict';
var kraken = require('kraken-js'),
express = require('express'),
request = require('supertest'),
should = require('chai').should(),
userApi = require('../lib/userApi'),
User = require('../models/user');
describe('#userApi tests', function() {
it('should insert an array of users using the userApi addUsers method', function(done) {
var users = [];
var user1 = {
firstName: 'test1',
lastName: 'test1',
password: 'abc123',
email: 'me1@here.com',
userName: 'test1'
};
var user2 = {
firstName: 'test2',
lastName: 'test2',
password: 'abc123',
email: 'me2@here.com',
userName: 'test2'
};
var user3 = {
firstName: 'test3',
lastName: 'test3',
password: 'abc123',
email: 'me3@here.com',
userName: 'test3'
};
users.push(user1);
users.push(user2);
users.push(user3);
//call the api and handle the promise that is returned
userApi.addUsers(users)
.then(function(results) {
should.exist(results);
//other assumptions here
done();
})
.fail(function(err) {
done(err);
})
});
});
I'm not a big fan of q
. I think is too much magic, so I rather use the native (on node@0.11.x) Promise
instead.
But if I understood it right, q.nbind
is a wrapper around the node's standard function call.
Maybe I would mimic its behavior using the new promise API as something like this.
promise = function () {
return new Promise(function(resolve, reject){
newUser.save(function(err, data){
if (err) return reject(err)
resolve(data)
})
})
}
I'm assuming that the newUser
is a mongoose model, and newUSer.save
only call the callback with an error parameter. Since data
is undefined, maybe q
doesn't call resolve with a falsy value.
I would try running your tests with this version of addUsers
instead.
var Promise = Promise || require('es6-promise').Promise // polyfill
, mongoose = require('mongoose')
;
function addUsers (users) {
return Promise.all(users.map(function(user){
return new Promise(function(resolve, reject){
var newUser = new User(user)
;
newUser.save(function(err){
if (err) return reject(err)
resolve()
})
})
}))
}
On the side, It looks like that the cool kids are using bluebird
this days for their promise fix.
It has great error handling (which is a problem with the native promise) and allow for custom builds.
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