Why save() in mongoose is not a function? - node.js

Question

I'm developing an app using Node.js, Mongoose, MongoDb, express.
I have 2 schemas one for student and one for snippets. I'm using the population model population model. I can create a user, and create a snippet and link it to the user. But I can't link and save the snippets in the user collection.
How to link and save the user so that it can have a reference to his snippets?
user and snippet schema
var userSchema = Schema({
name: { type: String, required: true, unique: true },
password: { type: String, required: true },
snippet: [{ type: Schema.Types.ObjectId, ref: 'Snippet' }]
})
var snippetSchema = Schema({
user: {type: Schema.Types.ObjectId, ref: 'User'},
title: String,
body: String,
createdAt: {
type: Date,
require: true,
default: Date.now
}
})
This is how I save the snippets I add it inside a user .save() function so that it saves the snippet ref but it gives me user.save() is not a function error.
var name = request.session.name.name
User.find({ name: name }).then(function (user) {
if (user) {
console.log('====================')
console.log(user)
user.save().then(function () { // problem is here?
var newSnippet = new Snippet({
user: user._id,
title: title,
body: snippet
})
newSnippet.save().then(function () {
// Successful
console.log('success')
response.redirect('/')
})
})
}
}).catch(function (error) {
console.log(error.message)
response.redirect('/')
})
But, I actually get the object printed after searching for it!
[ { _id: 5a2e60cf290a976333b19114,
name: 's',
password: '$2a$10$vD3EaQly4Sj5W3d42GcWeODuFhmHCSjfAJ1YTRMiYAcDBuMnPLfp6',
__v: 0,
snippets: [] } ]

Answer 1

You need to use User.findOne to get a valid user object, here you get an array. Also, don't forget to always return something in you promises (or throw an error).
Here is a quick rewrite of your function. With a few improvements such as arrow functions, const and a flat promise chain (never using any .then inside another .then) and avoiding code repetition
const name = request.session.name.name
User.findOne({ name })
.then(user => {
if (user) return user.save()
// What to do if not found? Throw an error?
throw new Error('User not found')
})
.then(() => {
const newSnippet = new Snippet({
user: user._id,
title: title,
body: snippet,
})
return newSnippet.save()
})
.catch((error) => console.log(error.message))
.then(() => response.redirect('/'))