object.js:20 Uncaught TypeError: Cannot convert undefined or null to object at Function.getOwnPropertyDescriptor

[artemgurzhii]

Versions:

• ember -> 3.4.8
• ember-data -> 3.4.4
• ember-decorators/argument -> 1.0.0-beta.2
• ember-decorators/babel-transforms -> ^3.1.0
• ember-decorators -> ^5.1.2

Error Message:

• object.js:20 Uncaught TypeError: Cannot convert undefined or null to object at Function.getOwnPropertyDescriptor (<anonymous>)

Error being thrown from the addon/-private/utils/object.js#L9-L16 Here is an image

I'm having simple component with optional arguments

// component.hbs
<ComponentName />  {{!-- This throws error --}}

<ComponentName
  @someProp={{"some string"}}
/>  {{!-- This does not --}}

// component.js
import Component from '@ember/component';
import { argument } from '@ember-decorators/argument';
import { optional } from '@ember-decorators/argument/types';

export default class ComponentNameComponent extends Component {
  @argument(optional('string')) someProp;
}

[willviles]

I'm experiencing this too whilst trying to upgrade from 0.5.0.

[alexlafroscia]

Sorry to hear there's been some issues upgrading -- thanks for checking out the beta version!

I upgraded out app at work recently and haven't run into this issue yet... I'm really curious what's different here. I guess I need to check that target is neither undefined ornull, since we pretty explicitly ensure that target is not undefined before passing it to getOwnPropertyDescriptors

Is there any chance you can set your debugger in Chrome (or whatever) to pause on uncaught errors, trigger the problem, and check that target is in fact null when the exception is thrown? That would make me feel quite a bit more confident in adding that additional check as the solution.

[artemgurzhii]

@alexlafroscia target is not null or undefined at first run, but method getPropertyDescriptor calls itself recursively

[alexlafroscia]

Interesting... I'll try to reproduce in a new Ember app with the dependencies that you've mentioned.

If you have a reproduction you can point me to, that would really speed things along!