Make load hooks more versatile

On the page I’m building with kit I need to display categories for a navigation component and want to highlight the active category (the currently viewed category or the category of the currently viewed entry). I see 3 possible approaches:

1. I could just retrieve the categories on each page where I need them, extract somehow the active category and give those as props to the Navigation component. This would mean much duplicated code and I think I would need to find an unique name for each query, right? Also it would be not good for caching, right?
2. Retrieve the categories in __layout.svelte, put them into a context and extract them where needed.
3. Retrieve the categories in __layout.svelte and pass them to further pages via the stuff property. This would mean that the afterLoad hook may return an LoadOutput object.

I think the third option would be the best (at least for kit, I did not look into how the kit code is wrapped for sapper) and implemented a PoC which works alright. Basically my modified code generates this as the load return:

  const _houdini_props = {
    _GetCategoriesPublic,
    _GetCategoriesPublic_Input: {},
    _GetCategoriesPublic_Source
  };
  if ("props" in _houdini_context.returnValue)
    return {
      ..._houdini_context.returnValue,
      props: {
        ..._houdini_context.returnValue.props,
        ..._houdini_props
      }
    };
  return {
    props: {
      ..._houdini_context.returnValue,
      ..._houdini_props
    }
  };

The fallback means I have to return something for the props key in __layout.sveltes afterLoad:

    return {
      props: {},
      stuff: {
        categories: data.GetCategoriesPublic.categories,
      },
    };

Would you be willing to implement something like this/accept a PR for this?

Then I would polish the code a bit and also handle returns from both beforeLoad and afterLoad.

[fehnomenal]

Glad you like it and that I can contribute to this great project 😃

I will prepare a PR but will probably need your help for adding some test cases 😅

[AlecAivazis]

Hey @fehnomenal! I’m a little distracted at the moment with some other work for Houdini so I haven’t found the time to look at your proposal but I will get to it as soon as I have some time. I didn’t want you to think I was ignoring you. Thanks for being patient!