Running yarn dev after a fresh clone & install fails due to duplicate babel plugin/preset

Hi! I just started your course and ran into an issue getting up and running. Upon running yarn dev, I see this error:

➜ yarn dev
yarn run v1.22.5
$ node ./server/index.js
⠋ Building...Serving on http://localhost:3000
🚨  /Users/josie.flynn/dev/professional-ts/src/index.js: Duplicate plugin/preset detected.
If you'd like to use two separate instances of a plugin,
they need separate names, e.g.

  plugins: [
    ['some-plugin', {}],
    ['some-plugin', {}, 'some unique name'],
  ]

Duplicates detected are:
[
  {
    "alias": "/Users/josie.flynn/dev/professional-ts/node_modules/@babel/plugin-proposal-class-properties/lib/index.js",
    "dirname": "/Users/josie.flynn/dev/professional-ts",
    "ownPass": false,
    "file": {
      "request": "@babel/plugin-proposal-class-properties",
      "resolved": "/Users/josie.flynn/dev/professional-ts/node_modules/@babel/plugin-proposal-class-properties/lib/index.js"
    }
  },
  {
    "alias": "base$1",
    "options": {
      "loose": "#__internal__@babel/preset-env__prefer-false-but-true-is-ok-if-it-prevents-an-error"
    },
    "dirname": "/Users/josie.flynn/dev/professional-ts",
    "ownPass": false

I think this is happening because @babel/preset-env now includes the @babel/plugin-proposal-class-properties proposal as of their 7.10.0 release: https://babeljs.io/blog/2020/05/25/7.10.0#class-properties-and-private-methods-to-shippedproposals-option-of-babelpreset-env-11451httpsgithubcombabelbabelpull11451

Commenting out "plugins": ["@babel/plugin-proposal-class-properties"] from .babelrc seems to resolve the issue for me.

Thanks for putting your course together, it’s been great so far! Just wanted to submit this in case it helps other folks who got stuck on it too.

[floroz]

Hi! I just started your course and ran into an issue getting up and running. Upon running yarn dev, I see this error:

➜ yarn dev
yarn run v1.22.5
$ node ./server/index.js
⠋ Building...Serving on http://localhost:3000
🚨  /Users/josie.flynn/dev/professional-ts/src/index.js: Duplicate plugin/preset detected.
If you'd like to use two separate instances of a plugin,
they need separate names, e.g.

  plugins: [
    ['some-plugin', {}],
    ['some-plugin', {}, 'some unique name'],
  ]

Duplicates detected are:
[
  {
    "alias": "/Users/josie.flynn/dev/professional-ts/node_modules/@babel/plugin-proposal-class-properties/lib/index.js",
    "dirname": "/Users/josie.flynn/dev/professional-ts",
    "ownPass": false,
    "file": {
      "request": "@babel/plugin-proposal-class-properties",
      "resolved": "/Users/josie.flynn/dev/professional-ts/node_modules/@babel/plugin-proposal-class-properties/lib/index.js"
    }
  },
  {
    "alias": "base$1",
    "options": {
      "loose": "#__internal__@babel/preset-env__prefer-false-but-true-is-ok-if-it-prevents-an-error"
    },
    "dirname": "/Users/josie.flynn/dev/professional-ts",
    "ownPass": false

I think this is happening because @babel/preset-env now includes the @babel/plugin-proposal-class-properties proposal as of their 7.10.0 release: https://babeljs.io/blog/2020/05/25/7.10.0#class-properties-and-private-methods-to-shippedproposals-option-of-babelpreset-env-11451httpsgithubcombabelbabelpull11451

Commenting out "plugins": ["@babel/plugin-proposal-class-properties"] from .babelrc seems to resolve the issue for me.

Thanks for putting your course together, it’s been great so far! Just wanted to submit this in case it helps other folks who got stuck on it too.

This worked for me too! thanks

// .babelrc.js
{
  "presets": [
    ["@babel/preset-env", { "targets": { "node": "10" } }],
    "@babel/preset-react",
    "@babel/preset-typescript"
  ]
  // "plugins": ["@babel/plugin-proposal-class-properties"]
}

[satyambnsal]

Thank you ❤️