What is the difference between Mongoose toObject and toJSON?

Question

The Mongoose documentation for toObject lists features, options, and gives examples of functionality of toObject.

The Mongoose documentation for toJSON says the options are the same as toObject, but doesn't explain what toJSON does. Elsewhere the documentation says

toJSON is exactly the same as the toObject option but only applies when the document's toJSON method is called.

Is toJSON an alias of toObject? If not, what are the differences?

Answer 1

A look at the source code reveals that both methods call an internal $toObject method, but with toJSON passing a second, true parameter:

Document.prototype.toObject = function (options) {   return this.$toObject(options); }; ... Document.prototype.toJSON = function (options) {   return this.$toObject(options, true); }; 

That second parameter determines whether $toObject uses the toJSON or toObject schema options for its defaults. So unless those schema options are configured differently, the two methods are identical.

Answer 2

Like JohnnyHK's anwser said, there is no difference between toJSON and toObject. My guess is that, toJSON was created to support the JSON.stringify method.

From the MDN document, if an object has the toJSON property as a function, JSON.stringify will use the toJSON function to serialize the object instead of the object itself.