Duplicated plugin

[tpai]

After run babel-upgrade, it create duplicate @babel/plugin-syntax-dynamic-import in .babelrc.

Version: 0.0.23

[nicolo-ribaudo]

What was your full original .babelrc?

[tpai]

Here it is.

{
  'presets': [
    ['env', {
      "targets": {
        "browsers": ["ie >= 11"]
      },
      "modules": false
    }],
    'stage-0',
    'react'
  ],
  'plugins': [
    'syntax-dynamic-import'
  ]
}

[nicolo-ribaudo]

This happens because you had the syntax-dynamic-import plugin duplicated (once in the preset and once explicitly in your config).

If anyone wants to look at this issue, it's because we "eject" the stage presets by replacing them with the plugins that they enable, without checking if those plugins are already there.

[claytonrcarter]

Not sure if this is the same issue, but I just ran npx babel-upgrade --write --install and almost everything worked fine, except for the following:

input

...
      "presets": [
      [
        "es2015",
        {
          "modules": false
        }
      ],
      [
        "env",
        {
          "modules": false
        }
      ]
    ],
...

output

...
    "presets": [
      [
        "@babel/preset-env",
        {
          "modules": false
        }
      ],
      [
        "@babel/preset-env",
        {
          "modules": false
        }
      ]
    ],
...

As I ponder it, it may be that the input was suboptimal (Babel & the various stage configs sometimes seems like black magic to me), but it worked, and afterward, it didn't. Removing the duplicate entry fixed the problem and everything started working again.

Thank you for this utility! I spent 4 hours trying to upgrade manually this morning w/ no luck. I started over and, aside from this hiccup, this utility did the job in a few minutes.