fix: handle null target instances passed to getPropertyDescriptor

[willviles]

This PR seeks to fix https://github.com/ember-decorators/argument/issues/98.

-private/utils/object.js#L10 was erroring because target passed to getPropertyDescriptor was in some cases null, not undefined.

export function getPropertyDescriptor(target, property) {
  if (target === undefined) return;
  // target = null...
  return (
    Object.getOwnPropertyDescriptor(target, property) ||
    getPropertyDescriptor(Object.getPrototypeOf(target), property)
  );
}

[alexlafroscia]

Thanks for submitting a PR for this! I actually came online just now to take a pass at solving it, but approving a PR is always better 😁

Did you try linking this locally and find that it solved the problem for you?

[artemgurzhii]

@alexlafroscia The problem I've described in the https://github.com/ember-decorators/argument/issues/98 is resolved with this PR, everything is working great.

@willviles Thanks!

[willviles]

@alexlafroscia yep, linked and it's removed all errors 👍 Not entirely sure whether this PR is the best possible solution, as it's just firefighting methodology. But in the mean time, it solves the problem!

[alexlafroscia]

That's OK as far as I'm concerned -- I'm unsure why I haven't come across this case where the prototype is null in my own codebases that are using this package without error right now.

Are you transpiling away native classes? We ship them in our codebase -- maybe that's the difference?

[willviles]

Yeah I'm shipping ES5, though I've just tried 1.0.0-beta.2 without transpiling native classes and the problem persists 🤷‍♂️

[willviles]

Out of interest, should default values still be respected when using the optional type? Here's what I'm getting:

// component.js
@argument('string')
foo = 'defaultValue'

{{! parent-template.hbs}}
<Component />

{{! component-template.hbs}}
{{log foo}} {{! => undefined}}

[artemgurzhii]

@willviles Same for me, I'll try to come up during this week with all the problems I'm having. I'm using es classes with angle bracket invocation syntax and sometimes I'm receiving unexpected errors(probably not because of angle invocation syntax feature, but I've not tried with the regular way)