Handle Object.freeze when used with EmberObject.extend()

[rwjblue]

When using:

export default Controller.extend({
  prop1: Object.freeze({ whatever: 'here' }),
})

The file is not transformed (due to the member expression for prop1). We have a few plausible solutions here. We know exactly what Object.freeze does, and can choose a few different paths forward:

1. Set prop1 on the prototype:

export default class Foo extend Controller {
}
Foo.prototype.prop1 = Object.freeze({ whatever: 'here' });

2. Set prop1 as a class field:

export default class Foo extend Controller {
  prop1 = { whatever: 'here' };
}

3. Something else?

[rwjblue]

I vaguely think we should do the second one, thoughts?

[pzuraq]

hmm, my main concern is the second solution is allowed to be stateful, which could be problematic. If it was truly meant to be a constant, I feel like it would make more sense to assign it as a static field (still frozen). That said, that isn't codemoddable, so this could work for now and we could guide people to transition toward that in the future.