Allow editing of defined DOM properties

[fluvf]

Ok, take number 23!
Now only changes element property handling and adds tests for it.

Crel now prioritizes element properties, if they're already defined, over adding / modifying attributes. This way you can edit properties like style or innerHTML, etc. using Crel, without having to use attrMap
This does remove the ability to use some reserved keywords in attributes, if you can't be certain that they are undefined, but I think that's bad practice, so we shouldn't encourage it anyways

Also updated the README to reflect these changes

[fluvf]

I'm working on tests next, and will add some for this there. But if you want, I can also add them into this pull request

[fluvf]

Currently this doesn't ignore null as the readme suggest, but I'll fix that in a follow up pr (or tomorrow)

[KoryNunn]

I would not like to allow the properties object in any other position than the second argument, it increases the surface area for testing, does not add any usability, and would probably decrease understandability.

Also, to implement this, there are multiple additional duck-typing checks per child added. This would likely have a notable impact on performance.

[KoryNunn]

I think I'm missing some tests, as these changes should fail tests. I'll have a look.

[KoryNunn]

These changes should fail this test: https://github.com/KoryNunn/crel/blob/master/test/index.js#L149

But there are too many conflicts for me to easily check this.

[fluvf]

I would not like to allow the properties object in any other position than the second argument, it increases the surface area for testing, does not add any usability, and would probably decrease understandability.

Also, to implement this, there are multiple additional duck-typing checks per child added. This would likely have a notable impact on performance.

Yeah, my original use case for that became obsolete, so I'll look into it after a rebase

[fluvf]

Rebased! No longer allows for multiple attributes objects to be passed. I also tried to make the changes a bit more incremental

[KoryNunn]

This looks like a helper for things like the style object? This is not really the intent of crel which aims to be extremely simple and raw. This is something that could easily be implemented in a more feature-rich module that uses crel under the covers.

[fluvf]

Isn't crel there to allow creating and editing ALL of the basic attributes and properties of an element? That's why I added the properties manipulation anyways. And with that in place it becomes kind of impossible to edit the style of an element through crel, because you can't access the attribute anymore.
On a side note, it's not specifically a helper for the style property, but then again I don't know if any other property is nested like that.

[fluvf]

Rebased. I split this into multiple prs. Currently based on #42, only adds the property changes. I'll open another pr for the invalid argument handling at some point

[fluvf]

final rebase
I don't need / see a use for the changes in this pr anymore (surprise surprise writing better code removes arbitrary use cases) so feel free to close this 👍

[KoryNunn]

No problems. Would you be able to let me know which of the other PRs I should look at and in which order?

[fluvf]

#46 and #47 (which is based on #46) in that order, thanks!