[breakpoints] add back deleted getWidth as width with a spec

[rosskevin]

@oliviertassinari deleted getWidth probably thinking it is unused. Well it is used and well loved by me ;).

Also updated the typescript, which was still expecting the old named fn.

[oliviertassinari]

What's the advantage of using it over values[key]?

[rosskevin]

LOL, primarily I had no idea it existed.

I think it's worth exposing it in the interface because otherwise you are making the user dig into the code to know that the values is actually a key map of width. This is true, but if it wasn't obvious to me as a maintainer, would it be apparent to one of our users?

[oliviertassinari]

@rosskevin I have been documenting the breaking change in the CHANGELOG.
Maybe this is a documentation issue?

[oliviertassinari]

I'm worried about extending the API where there is alternative, espically, when users can directly provides their own values property.

[rosskevin]

If they provide an incompatible values property, then they will also have to update the implementation of these methods.

So in the case of extension, it is better to expose an interface than an implementation detail.

[oliviertassinari]

@rosskevin But then, why not abstracting the following?

const theme = createMuiTheme({
  palette: {
    secondary: green,
  },
});

color: theme.palette.secondary.A200,

How is that more intuitive than?

const theme = createMuiTheme({
  breakpoints: {
    values: {
      sm: 788,
    }
  },
});


width: theme.breakpoints.values.sm,

[rosskevin]

I don't think your last comment is congruent with your previous postulate that user can provide their own values and that it somehow makes #width a risk.

Yes, accessing values seems quite reasonable, but I could argue that you should never expose values.

It is convenient, and obvious to have #width, that is all, and I do not agree that it is risky.

[oliviertassinari]

What do you mean by an invalid value property? type Breakpoint = 'xs' | 'sm' | 'md' | 'lg' | 'xl'; is not something they can change. They can only change the breakpoint width value.

[oliviertassinari]

@rosskevin Alright, at least we fixed the flow definitions :)