Find one or create with Mongoose

Question

I have

Page.findById(pageId).then(page => {   const pageId = page.id;    .. }); 

My problem is that if no page id is given, it should just take the first available page given some conditions, which is done by

Page.findOne({}).then(page => {   const pageId = page.id;   .. }); 

but if no page is found, it should create a new page and use this, which is done with

Page.create({}).then(page => {   const pageId = page.id;   .. }); 

But how do I combine all this to as few lines as possible?

I have a lot of logic going on inside

page => { ... } 

so I would very much like to do this smart, so I can avoid doing it like this

if (pageId) {   Page.findById(pageId).then(page => {     const pageId = page.id;      ..   }); } else {   Page.findOne({}).then(page => {     if (page) {       const pageId = page.id;       ..     } else {       Page.create({}).then(page => {         const pageId = page.id;         ..       });     }   }); } 

I am thinking I maybe could assign a static to the schema with something like

pageSchema.statics.findOneOrCreate = function (condition, doc, callback) {   const self = this;   self.findOne(condition).then(callback).catch((err, result) => {     self.create(doc).then(callback);   }); }; 

Answer 1

As per the Mongoose docs:

As per previous SO answer

Model.findByIdAndUpdate()

"Finds a matching document, updates it according to the update arg, passing any options, and returns the found document (if any) to the callback."

In the options set upsert to true:

upsert: bool - creates the object if it doesn't exist. defaults to false.

Model.findByIdAndUpdate(id, { $set: { name: 'SOME_VALUE' }}, { upsert: true  }, callback) 

Answer 2

Related to Yosvel Quintero's answer which didn't work for me:

pageSchema.statics.findOneOrCreate = function findOneOrCreate(condition, callback) {     const self = this     self.findOne(condition, (err, result) => {         return result ? callback(err, result) : self.create(condition, (err, result) => { return callback(err, result) })     }) } 

And then use it like:

Page.findOneOrCreate({ key: 'value' }, (err, page) => {     // ... code     console.log(page) })