feat(di): property injection with resolve

[bigopon]

📖 Description

Resolves #1742

🎫 Issues

Add an export resolve to support the use case described in #1742. So now it's simpler to do this

Before:

abstract class Base {
  constructor(obj1: SomeType, obj2: SomeType2) {}
}

@inject(SomeType, SomeType2)
class MyElement extends Base {
  constructor(obj1: SomeType, obj2: SomeType2) {
    super(obj1, obj2)
  }
}

After:

import { resolve } from 'aurelia';

abstract class Base {
  obj1 = resolve(SomeType);
  obj2 = resolve(SomeType2);
}

class MyElement extends Base {}

It's also possible to call resolve with multiple keys at once:

const [abc, all_def_instances, someOther] = resolve(Abc, all(Def), optional(SomeOtherClass));

Doc is up at https://docs.aurelia.io/getting-to-know-aurelia/dependency-injection-di#property-injection

[Sayan751]

Great work @bigopon! Just a bit curious about all those test* functions.

[Sayan751]

Is this required? Or just an overlooked cleanup? If this is really a test, consider moving it to the tests.

[bigopon]

This is to test the typing of our exports without having to have a dedicated place for it. Example is around the built-in resolver: all/lazy/factory. The reason is because they need to give the right resolved types when called with container.get, and resolve, as well as not yield any errors when used as decorators. These functions will be eliminated during the build as well. This is a good and simple way to have TS check on these complex types.

[Sayan751]

That's alright. I am not objecting to it. Rather, suggesting pushing it to tests, if the existing tests do not sufficiently cover this. And if they do cover, then these test* methods can be removed.

[bigopon]

Its a bit hard to test the api in the test project. Since this is just API design test, not runtime behavior test, having the test code next to the code is really beneficial. We have this in multiple decorator files. Though if we want to organise differently, one way we could do is to have separate test files, but right inside this project rather than test, so it doesnt pollute the normal code.