Proposal: rename button variants to follow the spec

[yuchi]

Material Guidelines changed the name of buttons’ variants. I’m proposing to update the variants name to follow the spec and implement those that are missing.

The rosetta stone is:

Material UI Beta 45	Current API	Material Guidelines	Proposed API
Flat Button	variant="flat"	Text Button	variant="text"
N/A	N/A	Outlined Button	variant="outlined
Raised Button	variant="raised"	Contained Button	variant="contained"
N/A	N/A	Toggle Button	toggled variant="outlined"

I’m not proposing a specific variant for Toggle Buttons because demos present them as button bars (hence could be a good idea have a specific component) where they are mostly outlined buttons with an additional toggled state, or Icon Buttons with different icons based on the state.

• I have searched the issues of this repository and believe that this is not a duplicate.

[oliviertassinari]

@mbrookes I'm not 💯% up-to-date with the latest improvements you did on this topic. Have we moved forward? At least, I know we gonna have to deprecate and remove the API at some point.

[gunn4r]

What about unelevated as well?

see:
https://material.io/develop/web/components/buttons/#variants
https://material-components.github.io/material-components-web-catalog/#/component/button

[oliviertassinari]

@gunn4r Can you find it in the official specificiation?

[gunn4r]

@oliviertassinari
Yeah I'm not seeing a reference to it here:
https://material.io/design/components/buttons.html

But you do find it in their official Design and API documentation:
https://material.io/develop/web/components/buttons/#variants

As well as their official button demo here:
https://material-components.github.io/material-components-web-catalog/#/component/button

[mbrookes]

I suggest we stick with the spec names, rather than what the MCW team are using.

[eps1lon]

Legacy variant names will be deprecated with 3.2.0 i.e. deprecation warnings will be logged. The flat and raised variants were already mapped to text and contained respectively.