Is there a way to set a default prototype?

Is there a way to set a default prototype? The following doesn't seem to work.

const {EventEmitter} = require('events')
const Crypto = ObjectModel({
  name: String
}).defaultTo(EventEmitter.prototype)

I'm setting the prototype as follows but it would be nice to have a default.

Object.setPrototypeOf(
  Crypto({
    name: 'Tezos'
  })
  , EventEmitter.prototype
)

Originally posted by @RichAyotte in #93 (comment)

It looks like base is hardcoded to Object, if I'm reading this correctly.

ObjectModel/src/object-model.js

Line 422 in 1c23c0f

return initModel(model, ObjectModel, def, Object)

Is setting the prototype a feature that you'd consider?

So, to make things clear and avoid confusion:

model instances inherit from the model prototype, that's why you put methods and other stuff in the prototype property of the model constructor, i.e. Crypto.prototype
with this prototype link, you get Crypto({ name: "Tezos" }) instanceof Crypto === true
if you reassign completely the prototype with Object.setPrototypeOf, you lose this link. This can cause some issues, for example if you have defined other stuff in ObjectModel.prototype or Model.prototype
the defaultTo is to used to set a default value to pass to the constructor when it is called without arguments. It does not change the model prototype and will not be used if a value is specified in the model constructor.

So the best option I think for your usecase is to use the extend method:
const Crypto = ObjectModel({ name: String }).extend(EventEmitter)

Basically it is equivalent to Object.assign(Crypto.prototype, EventEmitter.prototype) but let you override the model prototype afterwards if needed.

That definitely works. Not sure how I missed the extend method. The prototype remains Model but mixed in with EventEmitter prototype which is fine. Thank you for the detailed and quick response.

No problem, glad to help

@sylvainpolletvillard I spoke too fast. As soon as I tried to listen for an event, I got a TypeError. Here's the MWE.

'use strict'

const {EventEmitter} = require('events')
const {ObjectModel} = require('objectmodel')

const Bar = ObjectModel({
	name: String
}).extend(EventEmitter)

const bar = Bar({
	name: 'Foo'
})

bar.on('data', console.log)
bar.emit('data', 'hello world')

Error:

/node_modules/objectmodel/dist/object-model.js:102
		isModelInstance = i => i && is(Model, getProto(i).constructor),
		                                                 ^

TypeError: Cannot read property 'constructor' of null
    at isModelInstance (/node_modules/objectmodel/dist/object-model.js:102:52)
    at cast (/node_modules/objectmodel/dist/object-model.js:256:69)
    at getProxy (/node_modules/objectmodel/dist/object-model.js:288:36)
    at newPath (/node_modules/objectmodel/dist/object-model.js:332:38)
    at controlMutation (/node_modules/objectmodel/dist/object-model.js:226:5)
    at Object.set (/node_modules/objectmodel/dist/object-model.js:331:13)
    at _addListener (events.js:217:29)
    at Proxy.addListener (events.js:271:10)
    at Object.proxifyFn [as apply] (/node_modules/objectmodel/dist/object-model.js:292:26)
    at Object.<anonymous> (/src/ee-test.js:24:5)

Maybe you can shed some light on the importance of this check?

ObjectModel/src/object-model.js

Line 50 in 1c23c0f

isModelInstance = i => i && is(Model, getProto(i).constructor),

Would the following be a safe fix or would it potentially cause more problems?

isModelInstance = i => i && getProto(i) && is(Model, getProto(i).constructor),

Ah, right, this lib creates objects with no prototypes (https://github.com/Gozala/events/blob/master/events.js#L86 )

Your suggested fix looks perfect, let me add some tests and release a new patch version

Just released v3.7.7, can you confirm it fixes your issue ?

v3.7.7 works well. Thanks again!