Declaring defaults in your schema
Your schemas can define default values for certain paths. If you create a new document without that path set, the default will kick in.
var schema = new Schema({
name: String,
role: { type: String, default: 'guitarist' }
});
var Person = db.model('Person', schema);
var axl = new Person({ name: 'Axl Rose', role: 'singer' });
assert.equal(axl.role, 'singer');
var slash = new Person({ name: 'Slash' });
assert.equal(slash.role, 'guitarist');
var izzy = new Person({ name: 'Izzy', role: undefined });
assert.equal(izzy.role, 'guitarist');
Person.create(axl, slash, function(error) {
assert.ifError(error);
Person.find({ role: 'guitarist' }, function(error, docs) {
assert.ifError(error);
assert.equal(docs.length, 1);
assert.equal(docs[0].name, 'Slash');
});
});
Default functions
You can also set the default
schema option to a function. Mongoose will execute that function and use the return value as the default.
var schema = new Schema({
title: String,
date: {
type: Date,
// `Date.now()` returns the current unix timestamp as a number
default: Date.now
}
});
var BlogPost = db.model('BlogPost', schema);
var post = new BlogPost({title: '5 Best Arnold Schwarzenegger Movies'});
// The post has a default Date set to now
assert.ok(post.date.getTime() >= Date.now() - 1000);
assert.ok(post.date.getTime() <= Date.now());
The setDefaultsOnInsert
option
By default, mongoose only applies defaults when you create a new document. It will not set defaults if you use update()
and findOneAndUpdate()
. However, mongoose 4.x lets you opt-in to this behavior using the setDefaultsOnInsert
option.
Important
The setDefaultsOnInsert
option relies on the MongoDB $setOnInsert
operator. The $setOnInsert
operator was introduced in MongoDB 2.4. If you’re using MongoDB server < 2.4.0, do not use setDefaultsOnInsert
.
var schema = new Schema({
title: String,
genre: {type: String, default: 'Action'}
});
var Movie = db.model('Movie', schema);
var query = {};
var update = {title: 'The Terminator'};
var options = {
// Return the document after updates are applied
new: true,
// Create a document if one isn't found. Required
// for `setDefaultsOnInsert`
upsert: true,
setDefaultsOnInsert: true
};
Movie.
findOneAndUpdate(query, update, options, function (error, doc) {
assert.ifError(error);
assert.equal(doc.title, 'The Terminator');
assert.equal(doc.genre, 'Action');
});