Fixing "The new decorators proposal is not supported yet."

[tamatamvan]

Adding option decoratorsLegacy: true in @babel/preset-stage-2 for fixing this error :

Module build failed: Error: [BABEL] /path/to/project/src/main.js: The new decorators proposal is not supported yet. You must pass the `"decoratorsLegacy": true` option to @babel/preset-stage-2 (While processing: "/path/to/node_modules/@vue/babel-preset-app/index.js$1")

[silkentrance]

@tamatamvan please let the user pass in the decoratorsLegacy option so that he/she can decide whether to use that option. See the proposal by @soft903 #1162 (comment)

[tamatamvan]

hi @silkentrance , I'd made another change, so users can decide to use the option or not.
if there's another suggestions, please don't hesitate to tell me.

[jkzing]

Is this needed for preset-env?
It seems decoratorsLegacy only affects stage-0/1/2.

[hzoo]

yeah it's only for stage 0,1,2. It's one of the unfortunate issues related to having stage presets at all since you might not even use decorators. This is why after a lot of discussion may just want to remove them since it's just an array of plugins that will constantly changing babel/babel#7770.

It's fine to make it a top level option to pass to the other preset though.

[factoidforrest]

We should also lock the version of babel so this doesn't happen again. I was just talking to the Babel maintainers and they said that nobody should be using babel beta with a ^ because they WILL be breaking it more. They don't use it internally with a ^

[quantuminformation]

Just came across this in a brand new cli project

[yyx990803]

Just a note... vue-cli itself is in beta too.

[factoidforrest]

So it's good to be finding issues! We can't use `^` with Babel beta, they said it will continue to break and they aren't using it internally with a hat. Semver doesn't work with betas.

…

On Wed, Apr 25, 2018, 09:37 Evan You ***@***.***> wrote: Just a note... vue-cli itself is in beta too. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#1163 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAjhEgjymA14Xdeply5EUJsy2WKC_dBVks5tsHwVgaJpZM4TfZtm> .

[BenoitAverty]

Will this PR alone fix the problem ? How would I pass the option needed to the file that was just modified ?

[rynnova]

@BenoitAverty I have a local .babelrc which looks like this:

{
  "presets": [
    [
      "@vue/app",
      {
        "decoratorsLegacy": true
      }
    ]
  ]
}

This worked for me with the above patch.

[quantuminformation]

The above didn't work for me + "@babel/preset-stage-2": "7.0.0-beta.44"

 ERROR  Failed to compile with 1 errors                                                                                            08:29:08

 error  in ./src/main.js

Module build failed: Error: [BABEL] /Users/nikos/WebstormProjects/quantumjs2/src/main.js: The new decorators proposal is not supported yet. You must pass the `"decoratorsLegacy": true` option to @babel/preset-stage-2 (While processing: "/Users/nikos/WebstormProjects/quantumjs2/node_modules/@vue/babel-preset-app/index.js$1")

[quantuminformation]

I upgraded to beta 7, deleted and reinstalled node mods, and it worked