Implement Getters and setters for objects

[jasonwilliams]

We support getters and setters in our property descriptors, but we don't do anything with them.
In this example here: https://github.com/boa-dev/boa/blob/master/boa/src/object/internal_methods.rs#L102-L104 we check if a property exists, if it doesn't we should fallback to the getter and call that, but as you can see right now we just return undefined.

There will also need to be some syntax updates to support the get and set inside of objects, im not sure

Spec: https://tc39.es/ecma262/#sec-ordinary-object-internal-methods-and-internal-slots-get-p-receiver
MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/get

This code should now work and give the expected result:

let a = {
    get b() {
        return "test";
    }
}

a.b // "test"

Where to start

Running the above right now would give an error and land here:
https://github.com/boa-dev/boa/blob/master/boa/src/exec/object/mod.rs#L29

MethodDefinitionKind::Get would need to be implemented

[HalidOdat]

I will be working on the execution part of getters and setters (after some needed refactoring).

[HalidOdat]

This issue is blocked on:

• Object internal methods should live in GcObject (Move Object internal object methods to GcObject #835)
• Object internal methods should take a Context and return Result<T> (todo)

[Razican]

I believe this is implemented, right?

/cc @HalidOdat @tofpie

[tofpie]

As far as I can tell #986 is more or less a duplicate of this one, and it has been solved by #987.

[Razican]

As far as I can tell #986 is more or less a duplicate of this one, and it has been solved by #987.

Perfect, let's close this :)