Added support Bootstrap 4 Beta

[IvanKalinin]

This change is 

[justin808]

Is there a good reason to even support the alpha? We'll eventually move to only support the released version.

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Reviewed 3 of 3 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[IvanKalinin]

I think so.
Beta has a lot of changed. A lot of variables were renamed, so I think a lot of developers still use alpha 6. It could take a time to update their own project from alpha to beta. And we cannot break someones projects with updates

In my thoughts we can drop alpha in the next beta release

If you think I have to drop alpha - will do

[justin808]

@IvanKalinin Great work!

1. Let's remove all the beta parts. Alpha users should not upgrade.
2. Please update the CHANGELOG.md per prior entries for v2.2.0 and make any necessary changes in the README.md
3. Please confirm that you've tried all the examples in the examples directory and you've made the appropriate updates there so they are all on the beta and not the alpha.

Once the above 3 steps are done, I'll immediately create a new release for v2.2.0.

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Reviewed 1 of 1 files at r2.
Review status: all files reviewed at latest revision, 5 unresolved discussions.

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.bootstraprc-4-default, line 10 at r2 (raw file):

# If Bootstrap version 4-alphaX use `false`
# If Bootstrap version 4-betaX use `true`
isBeta: true

remove

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.bootstraprc-4-default, line 63 at r2 (raw file):

  # Reset and dependencies
  # Bootstrap dropped normalize in beta
  # Uncomment `normalize` if you still use alpha

Remove

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src/bootstrap.config.js, line 130 at r2 (raw file):

  return {
    bootstrapVersion: parseInt(userConfig.bootstrapVersion, 10),
    isBeta: userConfig.isBeta || false,

Do we still need this key? what purpose is it?

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src/bootstrap.styles.loader.js, line 25 at r2 (raw file):

    bootstrapRelPath,
    useFlexbox,
    isBeta,

remove

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src/bootstrap.styles.loader.js, line 50 at r2 (raw file):

  }

  if (bootstrapVersion === 4 && isBeta === true) {

remove conditional for beta

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Comments from Reviewable

[IvanKalinin]

There are a bit more changes.

[justin808]

Just one question in the code, that probably requires a doc note.

Please confirm all examples work and I'll merge and release.

GREAT WORK!

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Reviewed 23 of 23 files at r3.
Review status: all files reviewed at latest revision, 6 unresolved discussions.

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examples/basic/.bootstraprc-4-example, line 13 at r3 (raw file):

  - css-loader
  - sass-loader
  - postcss-loader

Why did this change? Just curious. Should we document this in the CHANGELOG or README? This is pretty subtle.

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Comments from Reviewable

[IvanKalinin]

Because order matters. Postcss loader should work after sass-loader. In that order there is no errors and warnings in console.

And yes, I tried all three examples with bs4

[netbull]

@justin808 any news when the PR will merged ?

[justin808]

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Review status: all files reviewed at latest revision, 6 unresolved discussions.

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Comments from Reviewable

[justin808]

Thanks @IvanKalinin!

[netbull]

Yes, thanks @IvanKalinin

[kuongknight]

I still found issue : Argument $color of darken($color, $amount) must be a color
When using:
bootstrap-loader: 2.2.0
bootstrap: 4.0.0-beta.3
default .bootstraprc-4-default

[justin808]

@kuongknight maybe submit a PR?