Introduce BoxEdges typedef.

[jodator]

Suggested merge commit message (convention)

Docs: Introduce BoxEdges type definition. Closes ckeditor/ckeditor5#6132.

ps.: I've also removed the TopRifghtBottomLeft nomenclature from methods and used BoxEdges instead. I think that this is way better then previous.

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Additional information

• I was annoyed to describe this object over and over again in I/3287: Table and table cell properties plugins ckeditor5-table#224.

[coveralls]

Coverage remained the same at 100.0% when pulling b488001 on i/6132 into b2a8189 on master.

[oleq]

A good idea but the word choice is wrong IMO.

[oleq]

I think it should rather be box sides instead. Check out how w3 uses both terms https://www.w3.org/TR/CSS2/box.html (search for both):

These are for edges:

The perimeter of each of the four areas (content, padding, border, and margin) is called an "edge", so each box has four edges:

• content edge or inner edge
• padding edge
• border edge
  ...

These are for sides (and IMO this is what we want to say):

The 'padding' shorthand property sets the padding for all four sides while the other padding properties only set their respective side.

If there is only one component value, it applies to all sides. If there are two values, the top and bottom paddings are set to the first value and the right and left paddings are set to the second.

The 'border-color' property can have from one to four component values, and the values are set on the different sides as for 'border-width'.

Summary

So edges are more like contours around the box (containing or not containing the padding, border, etc.) and the box has always 4 sides (top, left, bottom, right).

[jodator]

Thanks! I've looked at MDN docs and saw the edges used mostly. But your explanaition & wording is better. I'll fix that :)

[oleq]

What do we do about https://ckeditor.com/docs/ckeditor5/latest/api/module_utils_dom_getborderwidths.html#static-function-getBorderWidths? It should use the same typedef.

Is it OK if it used the typedef from the engine? Or maybe the typedef should be defined somewhere else?

[jodator]

Is it OK if it used the typedef from the engine? Or maybe the typedef should be defined somewhere else?

IDK to be fair... I'll just write what comes to my mind:

1. it would be nice to have one typedef for that
2. OTOH we cannot introduce circular dependency engine -> utils -> engine
3. I can live with no typedef for utils stuff
4. I've just check and we already use module:engine/view/observer in keystrokehandler docs

...

I'd go with a follow up to iron this out (as the keystroke handler looks like in wrong place)