Research: Set goals for and discuss cascading scale

[benelan]

Background

Continuing the Teams discussion on #2781 about how we want to handle cascading scale. One of the options was to use a -- var for scale and remove the prop. Another option was not cascading and having the user set the prop on all of the components that they want to change.

Desired Outcome

• Create pros/cons for the options above as well as any other ways to handle cascading scale
• Make sure the solution is consistent for the end user

[driskull]

By their nature, HTML props aren't supposed to cascade. I think if we want scale to cascade, we should look into using a CSS custom property for it.

If we're ok with a prop scale not cascading then we just don't have it cascade.

In case of the dir property, it really just sets a CSS property direction:. So we could do the same if we really wanted to but in the end it should be the CSS that is doing the cascading. eg: scale prop just sets a CSS property that each component can use. I prefer a class because its more global. dir is a global attribute but we can't set a global attribute like that.

[patrickarlt]

In looking into #3624 it might be nice to split scale into 2 parts:

1. text scale
2. "size" scale

In the case of #3624 I could then set the "size" scale so the components are the same height and the text scale to the same level to ensure the text stays the same size.

[jcfranco]

Discussed with the team and we will not pursue cascading scale via props outside of parent/child structures (e.g., accordion/accordion-item). Doing so introduces opportunities for unintentional scale overrides across subtrees. I'll submit a separate issue to drop any scale lookups outside of this (looks like it's just the input components) Our inputs are looking up scale and status to not break label's described behavior. These will be removed in 1.0.0 (see #3781).

[jcfranco]

@patrickarlt Apologies for the belated reply. Could you provide additional info about the use case? + @macandcheese @SkyeSeitz @ashetland for design considerations regarding separate text/size scale. We can also move this to a separate discussion.