feat(babel-preset-app): change default core-js to v3

[clarkdo]

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

As core-js@2 has been deprecated officially, we can change default version to v3 now.

https://www.npmjs.com/package/core-js/v/2.6.10

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly. (PR: #)
• I have added tests to cover my changes (if not applicable, please state why)
• All new and existing tests are passing.

[TheAlexLichter]

This will be a breaking change, right?

[codecov-io]

Codecov Report

Merging #6721 into next will decrease coverage by 0.2%.
The diff coverage is 28.2%.

@@            Coverage Diff             @@
##             next    #6721      +/-   ##
==========================================
- Coverage   62.47%   62.27%   -0.21%     
==========================================
  Files          82       82              
  Lines        3310     3332      +22     
  Branches      902      905       +3     
==========================================
+ Hits         2068     2075       +7     
- Misses        997     1009      +12     
- Partials      245      248       +3

Flag	Coverage Δ
#unittests	62.27% <28.2%> (-0.21%)	⬇️

Impacted Files	Coverage Δ
packages/vue-app/src/index.js	0% <ø> (ø)	⬆️
packages/core/src/nuxt.js	93.18% <ø> (ø)	⬆️
packages/webpack/src/utils/postcss.js	1.19% <0%> (-0.15%)	⬇️
packages/vue-renderer/src/renderers/ssr.js	0% <0%> (ø)	⬆️
packages/vue-renderer/src/renderers/modern.js	0% <0%> (ø)	⬆️
packages/utils/src/modern.js	100% <100%> (ø)	⬆️

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[clarkdo]

@manniL I think it's not a breaking change since user won't change anything for it.

We fixed the core-js version at v2 because v3 was just released and there are issues due to nested/hoisting in different version.

Now, v3 has been released for 8 months and v2 has been deprecated officially, so I think it's the time to upgrade it.

[clarkdo]

@manniL Oh, one potential breaking change could be: User installed core-js@2 manually but doesn't configure corejs: 2.

@nuxt/core-team What you think if we put notification in release note and doc, then release it as a feature in next minor release ?

[galvez]

@nuxt/core-team What you think if we put notification in release note and doc, then release it as a feature in next minor release ?

Sounds good to me. Must be done carefully or we'll have a slew of bug reports due to a bad package-lock.json.

[TheAlexLichter]

We should definitely give it a try but we have to assess the changes properly to avoid another bunch of core-js issues. IRC some projects, e.g. vue-cli, bumped the core-js version up to 3 in a major release.

[pi0]

Indeed we need to be careful about bumping to 3. Le'ts hold this on until next team meeting.

[clarkdo]

@pi0 @manniL I've added a core-js version checking, so I think it should be OK to migrate to v3 in next minor release as core-js@2 has been deprecated officially.

[garrensweet]

bump

[clarkdo]

@pi0 @manniL I've added a core-js version checking, so I think it should be OK to migrate to v3 in next minor release as core-js@2 has been deprecated officially.

@pi0 Can you please have a look at latest change ?

[clarkdo]

cc @pi0