I want to add to the return data from a mongoose query:
User.findById(userId, function(err, data) {
if (!err) {
data.newvar = 'Hello, world';
}
});
However, when I console log the output, the newvar does not exist. I've also tried this using Underscore's extend:
_.extend(data, {'newvar': 'Hello, world'});
With no luck either. Since I have nested documents, using a shallow copy won't work. Is there any way to append data here?
One way to handle this is to convert your mongoose model instance into a plain object that you have full control over by calling toObject() on it:
User.findById(userId, function(err, data) {
if (!err) {
data = data.toObject();
data.newvar = 'Hello, world';
}
});
If you want a more structured solution, you can add virtual attributes to your schema as described here.
As it turns out, Mongoose documents are their own special class and not standard Javascript objects. In order to get a javascript option that can be extended, you must use the toObject() method.
Now you can use lean() method to return a plain js object:
User.findById(userId)
.lean()
.exec( function(err, data) {
if (!err) {
data.newvar = 'Hello, world';
}
});
Why can't you modify the data returned by a Mongoose Query (ex: findById)
Related
When a user submits a form on my site, I want to show them three items: a breakfast item, a lunch item, and a dinner item. To do this, I thought I'd have to individually do a db.collection("recipes").findOne, then return the result of that code to a variable I could then pass to EJS using res.render("meal-plan", {breakfast:breakfast});
However, it turns out the variables gathered from the findOne query must be passed to EJS before the findOne query is closed or else you can't access them. Now I'm stuck with something like this:
var breakfast;
MongoClient.connect('mongodb://localhost', function (err, client) {
if (err) throw err;
var db = client.db('food_app');
db.collection("recipes").findOne({ "breakfast" : true}, function(err, result) {
if (err) {
console.log(err);
} else {
console.log(result.title);
breakfast = result;
client.close();
}
res.render("meal-plan.ejs", {breakfast:breakfast});
});
});
This successfully allows me to pass the breakfast variable to EJS. However, I want to have multiple variables to pass (breakfast, lunch, dinner). How can I do this if I can only pass one variable? Is it acceptable to use multiple res.renders in multiple queries so I can copy/paste the MongoClient code three times or put it in a function?
In meal-plan.ejs, you should use forEach
See more at https://ejs.co
<%breakfast.forEach(bf){%>
<p><%bf.name%></p>
<%}%>
In Mongoose, I can use a query populate to populate additional fields after a query. I can also populate multiple paths, such as
Person.find({})
.populate('books movie', 'title pages director')
.exec()
However, this would generate a lookup on book gathering the fields for title, pages and director - and also a lookup on movie gathering the fields for title, pages and director as well. What I want is to get title and pages from books only, and director from movie. I could do something like this:
Person.find({})
.populate('books', 'title pages')
.populate('movie', 'director')
.exec()
which gives me the expected result and queries.
But is there any way to have the behavior of the second snippet using a similar "single line" syntax like the first snippet? The reason for that, is that I want to programmatically determine the arguments for the populate function and feed it in. I cannot do that for multiple populate calls.
After looking into the sourcecode of mongoose, I solved this with:
var populateQuery = [{path:'books', select:'title pages'}, {path:'movie', select:'director'}];
Person.find({})
.populate(populateQuery)
.execPopulate()
you can also do something like below:
{path:'user',select:['key1','key2']}
You achieve that by simply passing object or array of objects to populate() method.
const query = [
{
path:'books',
select:'title pages'
},
{
path:'movie',
select:'director'
}
];
const result = await Person.find().populate(query).lean();
Consider that lean() method is optional, it just returns raw json rather than mongoose object and makes code execution a little bit faster! Don't forget to make your function (callback) async!
This is how it's done based on the Mongoose JS documentation http://mongoosejs.com/docs/populate.html
Let's say you have a BookCollection schema which contains users and books
In order to perform a query and get all the BookCollections with its related users and books you would do this
models.BookCollection
.find({})
.populate('user')
.populate('books')
.lean()
.exec(function (err, bookcollection) {
if (err) return console.error(err);
try {
mongoose.connection.close();
res.render('viewbookcollection', { content: bookcollection});
} catch (e) {
console.log("errror getting bookcollection"+e);
}
//Your Schema must include path
let createdData =Person.create(dataYouWant)
await createdData.populate([{path:'books', select:'title pages'},{path:'movie', select:'director'}])
I have my Model as
var Model = {"name":String,"email":String,"notes":[{"time":Date,"title":String,"description":String}]
And I want to find document based on the email, and then add a note to the array. And then save it back.
What I tried is,
var updatedNote = {};
Model.findOne({'email':'test#test.com'},function(err, note){
for(var property in note._doc){
if(note._doc.hasOwnProperty(property)){
updatedNote[property] = note._doc[property];
};
}
updatedNote.notes.push(newNote);
note._doc = updatedNote;
note.save(function(err){
if(err){
console.log(error);
}
else {
res.redirect('/notes');
}
})
});
But it is throwing error as "Object does not have save method". I don't want to use findByIdAndUpdate() as i am leaving this responsibility of generating id on mongo.
I don't understand what most of that code is doing. If I wanted to add a note to the document (I'm assuming newNote is defined elsewhere), I'd just do:
Model.findOne({'email':'test#test.com'},function(err, note){
note.notes.push(newNote);
note.save(function(err){});
});
I'm using the request library to make calls from one sails app to another one which exposes the default blueprint endpoints. It works fine when I query by non-id fields, but I need to run some queries by passing id arrays. The problem is that the moment you provide an id, only the first id is considered, effectively not allowing this kind of query.
Is there a way to get around this? I could switch over to another attribute if all else fails but I need to know if there is a proper way around this.
Here's how I'm querying:
var idArr = [];//array of ids
var queryParams = { id: idArr };
var options: {
//headers, method and url here
json: queryParams
};
request(options, function(err, response, body){
if (err) return next(err);
return next(null, body);
});
Thanks in advance.
Sails blueprint APIs allow you to use the same waterline query langauge that you would otherwise use in code.
You can directly pass the array of id's in the get call to receive the objects as follows
GET /city?where={"id":[1, 2]}
Refer here for more.
Have fun!
Alright, I switched to a hacky solution to get moving.
For all models that needed querying by id arrays, I added a secondary attribute to the model. Let's call it code. Then, in afterCreate(), I updated code and set it equal to the id. This incurs an additional database call, but it's fine since it's called just once - when the object is created.
Here's the code.
module.exports = {
attributes: {
code: {
type: 'string'//the secondary attribute
},
// other attributes
},
afterCreate: function (newObj, next) {
Model.update({ id: newObj.id }, { code: newObj.id }, next);
}
}
Note that newObj isn't a Model object as even I was led to believe. So we cannot simply update its code and call newObj.save().
After this, in the queries having id arrays, substituting id with code makes them work as expected!
I am trying to fetch all the records but with selected fields, I have tried the following ways but none works:
Post.find(
{
where: {},
select: ['title']
}
);
Post.find(
{},
{
fields: {
title: 1
}
}
);
As this answer points out, the fields param "WILL work as long as you pass other params with it such as limit or order."
Alternatively, if you want this throughout your application, you could define a custom toJSON function for your model, under attributes. If not, you could still define it under some other (e.g. filter) and use map to return the custom objects instead of the default model. Remember to take care of the control flow while using map though. Use async/promises/raw logic to avoid returning before all objects are processed.
The issue has been resolved in sails-mongo latest version:
https://github.com/balderdashy/waterline/issues/1098
Thanks
I've played with trying to get above answer to use limit or order to kick in the projection to no avail.
I did see this in the docs located here:
http://sailsjs.org/documentation/reference/waterline-orm/models/native
With an out of the box solution for exactly what you're doing (pasted here for ease of use).
Pet.native(function(err, collection) {
if (err) return res.serverError(err);
collection.find({}, {
name: true
}).toArray(function (err, results) {
if (err) return res.serverError(err);
return res.ok(results);
});
});
Swap out the response base things and change Pet to Post and, this ought to work in the sails console:
Post.native(function(err, collection) {
if (err) throw new Error(err);
collection.find({}, {
title: true
}).toArray(function (err, results) {
if (err) throw new Error(err);
console.log(results);
});
});
You'll still get the _id field, and if you don't want that then hit the Mongo docs on not getting those hint(title: true, _id: false)hint
Hope this helps!