Develop Reference

mongoosejs - find() using nested objects

question is possibly a duplicate but I haven't found anything that provides an appropriate answer to my issue.
I have an ExpressJS server which is used to provide API requests to retrieve data from a MongoDB database. I am using mongoosejs for the MongoDB connection to query/save data.
I am building a route that will allow me to find all data that matches some user input but I am having trouble when doing the query. I have spent a long while looking online for someone with a similar issue but coming up blank.
I will leave example of the code I have at the minute below.
code for route
// -- return matched data (GET)
router.get('/match', async (req, res) => {
const style_data = req.query.style; // grab url param for style scores ** this comes in as a string **
const character_data = req.query.character; // grab url param for character scores ** this comes in as a string **
// run matcher systems
const style_matches = style_match(style_data);
res.send({
response: 200,
data: style_matches
}); // return data
});
code for the query
// ---(Build the finder)
const fetch_matches_using = async function(body, richness, smoke, sweetness) {
return await WhiskyModel.find({
'attributes.body': body,
'attributes.richness': richness,
'attributes.smoke': smoke,
'attributes.sweetness': sweetness
});
}
// ---(Start match function)---
const style_match = async function (scores_as_string) {
// ---(extract data)---
const body = scores_as_string[0];
const richness = scores_as_string[1];
const smoke = scores_as_string[2];
const sweetness = scores_as_string[3];
const matched = [];
// ---(initialise variables)---
let match_count = matched.length;
let first_run; // -> exact matches
let second_run; // -> +- 1
let third_run; // -> +- 2
let fourth_run; // -> +- 3
// ---(begin db find loop)---
first_run = fetch_matches_using(body, richness, smoke, sweetness).then((result) => {return result});
matched.push(first_run);
// ---(return final data)---
return matched
}
example of db object
{
_id: mongoid,
meta-data: {
pagemd:{some data},
name: whiskyname
age: whiskyage,
price: price
},
attributes: {
body: "3",
richness: "3",
smoke: "0",
sweetness: "3",
some other data ...
}
}
When I hit the route in postman the JSON data looks like:
{
response: 200,
data: {}
}
and when I console.log() out matched from within the style match function after I have pushed the it prints [ Promise(pending) ] which I don't understand.
if I console.log() the result from within the .then() I get an empty array.
I have tried using the populate() method after running the find which does technically work, but instead of only returning data that matches it returns every entry in the collection so I think I am doing something wrong there, but I also don't see why I would need to use the .populate() function to access the nested object.
Am I doing something totally wrong here?
I should also mention that the route and the matching functions are in different files just to try and keep things simple.
Thanks for any answers.

just posting an answer as I seem to have fixed this.
Issue was with my .find() function, needed to pass in the items to search by and then also a call back within the function to return error/data. I'll leave the changed code below.
new function
const fetch_matches_using = async function(body, richness, smoke, sweetness) {
const data = await WhiskyModel.find({
'attributes.body': body,
'attributes.richness': richness,
'attributes.smoke': smoke,
'attributes.sweetness': sweetness
}, (error, data) => { // new ¬
if (error) {
return error;
}
if (data) {
console.log(data)
return data
}
});
return data; //new
}
There is still an issue with sending the found results back to the route but this is a different issue I believe. If its connected I'll edit this answer with the fix for that.

Yeoman invoke generator by code with args

I've having yeoman generator with sub generator.
I need to invoke the sub generator via code and I use the code below which is working, I see that the sub generator is invoked and I got the question in the terminal.
docs:
https://yeoman.io/authoring/integrating-yeoman.html
var yeoman = require('yeoman-environment');
var env = yeoman.createEnv();
env.lookup(function () {
env.run('main:sub',err => {
console.log('done' ,err);
});
});
The sub generator have only one question
prompting() {
const prompts = [
{
name: "app",
message: "which app to generate?",
type: "input",
default: this.props.app,
},
];
...
I want to call it silently, which means to pass the value for app question via code and not using terminal and I try this which doesn't works, (I see the question in the terminal)
env.lookup(function () {
env.run('main:sub',{"app":"nodejs"}, err => {
console.log('done' ,err);
});
});
and also tried this which doesnt works
env.lookup(function () {
env.run('main:sub --app nodejs', err => {
console.log('done' ,err);
});
});
How can I do it ? pass the values using code (maybe like it's done on unit test but this code is not unit test... when the terminal is not invoked)
From the docs im not sure how to pass the values
https://yeoman.io/authoring/integrating-yeoman.html
I've also found this but didn't quite understand how to use it to pass parameter to generator
http://yeoman.github.io/environment/Environment.html#.lookupGenerator
is it possible?

You can just do:
env.lookup(function () {
env.run('main:sub',{"app":"nodejs"}, err => {
console.log('done' ,err);
});
});
and inside the sub sub-generator, you can find the value via this.options.app.
To disable the question prompt, defined when field inside the Question Object like this:
prompting() {
const prompts = [
{
name: "app",
message: "which app to generate?",
type: "input",
default: this.props.app,
when: !this.options.app
},
];
. . .
return this.prompt(prompts).then((props) => {
this.props = props;
this.props.app = this.options.app || this.props.app;
});
}

What is the best way to approach chaining callbacks in javascript / typescript

I want to have a single endpoint that does this:
Create House and store in the database.
When we know it has been stored in the database, we create pricing for it, saved to the database as well.
Then query the Pricing Table using "type_of_room", get the average of price, and use the price to calculate the new proposed price.
Problem : I am passing the data here but it is not working when i console log it outside the callback : avgPricePerSquareMetre = data[0].getDataValue("price");
Problem 2: Even if the problem one is solved, I do not know how to save the Pricing yet again since I only want to pass the new proposed price to the Pricing table.
What is the best practice on how to handle this, please? Any suggestions?
I believe I am missing something here but I do not know what it is.
router.post("/register", (req: Request, res: Response) => {
let propertyData: object;
let test: any;
let avgPricePerSquareMetre: number;
const property = new House({
... // some req body data.
});
property
.save()
.then((data) => {
propertyData = data;
if (!data) {
return res.status(422).json(`Infomation could not be processed.`);
}
const pricing = new Pricing({
... // some req body data.
});
pricing.save().then((data) => {
if (!data) {
return res.status(422).json(`Infomation could not be processed.`);
}
Pricing.findAll({
attributes: [
"type_of_room",
[
Sequelize.fn("AVG", Sequelize.col("price")),
"price",
],
],
group: "type_of_room",
order: [
[Sequelize.fn("AVG", Sequelize.col("price")), "DESC"],
],
}).then((data) => {
if (data) {
// Data passed : Confirmed working until here.
avgPricePerSquareMetre = data[0].getDataValue("price");
}
});
console.log("avgPricePerSquareMetre - 1", avgPricePerSquareMetre);
// --> THIS ISSUE : this data is not being passed to avgPricePerSquareMetre
});
return res.status(201).json({
created: true,
avg_price_per_square_metre: avgPricePerSquareMetre,
});
})
.catch((error) => {
console.log(error);
return res.status(500).json({
error: error,
});
});
}

GraphQL query returns error "Cannot return null for non-nullable field"

I have a basic GraphQL query setup as follows:
Query.js:
const Query = {
dogs(parent, args, ctx, info) {
return [{ name: 'Snickers' }, { name: 'Sunny' }];
},
};
module.exports = Query;
schema.graphql:
type Dog {
name: String!
}
type Query {
dogs: [Dog]!
}
I created a function createServer() for starting the server as follows:
const { GraphQLServer } = require('graphql-yoga');
const Mutation = require('./resolvers/Mutation');
const Query = require('./resolvers/Query');
const db = require('./db');
function createServer() {
return new GraphQLServer({
typeDefs: 'src/schema.graphql',
resolvers: {
Mutation,
Query,
},
resolverValidationOptions: {
requireResolversForResolveType: false,
},
context: req => ({ ...req, db }),
});
}
module.exports = createServer;
I then tried querying dogs as follows:
query {
dogs {
name
}
}
But instead of getting the names from the array of dogs, I got the following error instead:
{
"data": null,
"errors": [
{
"message": "Cannot return null for non-nullable field Query.dogs.",
"locations": [
{
"line": 2,
"column": 3
}
],
"path": [
"dogs"
]
}
]
}
What seems to be causing this error?

This problem comes from AWS requiring certain standard values in the dynamoDB table, such as createdAt and updatedAd, just add these fields manually with a timestamp in dynamo db for further testing. A mutation always needs to be requested via id, this somehow was not clear to me when my schema was created by amplify codegen...

The above code works as you can see in codesandbox: https://codesandbox.io/s/olzj9vvpk5
But when I convert Query to something like {} it returns the same error so please check your paths and console.log Query to validate the path. Your export looks correct but you might have forgotten to save the file as I can see from the course starter files Query is an {}. Please double check.
Also if this code is in a public git repo please share the link.

I know this question has been answered, but for me the only thing that fixed this issue was to also pass the info argument.

In my case, I create a new Query.js file at the src folder but I import Query with Query = require('./resolvers/Query') and coding there. So, try to check the path, I think the problem is there.

How to exclude one particular field from a collection in Mongoose?

I have a NodeJS application with Mongoose ODM(Mongoose 3.3.1). I want to retrieve all fields except 1 from my collection.For Example: I have a collection Product Which have 6 fields,I want to select all except a field "Image" . I used "exclude" method, but got error..
This was my code.
var Query = models.Product.find();
Query.exclude('title Image');
if (req.params.id) {
Query.where('_id', req.params.id);
}
Query.exec(function (err, product) {
if (!err) {
return res.send({ 'statusCode': 200, 'statusText': 'OK', 'data': product });
} else {
return res.send(500);
}
});
But this returns error
Express
500 TypeError: Object #<Query> has no method 'exclude'.........
Also I tried, var Query = models.Product.find().exclude('title','Image'); and var Query = models.Product.find({}).exclude('title','Image'); But getting the same error. How to exclude one/(two) particular fields from a collection in Mongoose.

Use query.select for field selection in the current (3.x) Mongoose builds.
Prefix a field name you want to exclude with a -; so in your case:
Query.select('-Image');
Quick aside: in JavaScript, variables starting with a capital letter should be reserved for constructor functions. So consider renaming Query as query in your code.

I don't know where you read about that .exclude function, because I can't find it in any documentation.
But you can exclude fields by using the second parameter of the find method.
Here is an example from the official documentation:
db.inventory.find( { type: 'food' }, { type:0 } )
This operation returns all documents where the value of the type field is food, but does not include the type field in the output.

Model.findOne({ _id: Your Id}, { password: 0, name: 0 }, function(err, user){
// put your code
});
this code worked in my project. Thanks!! have a nice day.

You could do this
const products = await Product.find().select(['-image'])

I am use this with async await
async (req, res) => {
try {
await User.findById(req.user,'name email',(err, user) => {
if(err || !user){
return res.status(404)
} else {
return res.status(200).json({
user,
});
}
});
} catch (error) {
console.log(error);
}

In the updated version of Mongoose you can use it in this way as below to get selected fields.
user.findById({_id: req.body.id}, 'username phno address').then(response => {
res.status(200).json({
result: true,
details: response
});
}).catch(err => {
res.status(500).json({ result: false });
});

I'm working on a feature. I store a userId array name "collectedUser" than who is collected the project. And I just want to return a field "isCollected" instead of "collectedUsers". So select is not what I want. But I got this solution.
This is after I get projects from database, I add "isCollected".
for (const item of projects) {
item.set("isCollected", item.collectedUsers.includes(userId), {
strict: false,
})
}
And this is in Decorator #Schema
#Schema({
timestamps: true,
toObject: {
virtuals: true,
versionKey: false,
transform: (doc, ret, options): Partial<Project> => {
return {
...ret,
projectManagers: undefined,
projectMembers: undefined,
collectedUsers: undefined
}
}
}
})
Finally in my controller
projects = projects.map(i => i.toObject())
It's a strange tricks that set undefined, but it really work.
Btw I'm using nestjs.

You can do it like this
const products = await Product.find().select({
"image": 0
});

For anyone looking for a way to always omit a field - more like a global option rather than doing so in the query e.g. a password field, using a getter that returns undefined also works
{
password: {
type: String,
required: true,
get: () => undefined,
},
}
NB: Getters must be enabled with option { toObject: { getters:true } }

you can exclude the field from the schema definition
by adding the attribute
excludedField : {
...
select: false,
...
}
whenever you want to add it to your result,
add this to your find()
find().select('+excludedFiled')