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react-nativepluginsbabeljsmobx

the experimental syntax 'decorators-legacy is not supported and shows an error when i try to use mobx tools on my react app

Hey I Have been trying to add @observer to my react component but this error occurs : Support for the experimental syntax 'decorators-legacy' isn't currently enabled here are the steps I have taken:

1.npm install mobx --save and npm i mobx mobx-react --save

  1. tried using observable did not work

  2. added

    [ require(‘@babel/plugin-proposal-decorators’).default, { legacy: true } ],

didn't work so i removed it

  1. Created .babelrc in at the root directory and added

    { "presets": ["react-native"], "plugins": [ [ "@babel/plugin-proposal-decorators", { "legacy": true } ] ] }

and still not working

Editing:

I did what you just said and same error:

when I npm start -- --reset-cache, this appears on my terminal, maybe it might help:

Emitted 'error' event at:
    at Server.WebSocketServer._onServerError (/Users/red/mApp/node_modules/ws/lib/WebSocketServer.js:82:50)
    at Server.emit (events.js:202:15)
    at emitErrorNT (net.js:1283:8)
    at processTicksAndRejections (internal/process/next_tick.js:76:17)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] start: `node node_modules/react-native/local-cli/cli.js start "--reset-cache"`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

Package.json file

{
  "name": "mapp",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "node node_modules/react-native/local-cli/cli.js start",
    "test": "jest"
  },
  "dependencies": {
    "@expo/vector-icons": "^10.0.2",
    "babel-plugin-mobx-deep-action": "^1.6.1",
    "jetifier": "^1.6.3",
    "jsc-android": "241213.x.x",
    "mobx": "^5.11.0",
    "mobx-react": "^6.1.1",
    "react": "16.8.3",
    "react-native": "^0.59.10",
    "react-native-background-fetch": "^2.6.0",
    "react-native-background-geolocation": "^3.0.7",
    "react-native-css-gradient": "^0.3.1",
    "react-native-gesture-handler": "^1.3.0",
    "react-native-ionicons": "^4.5.6",
    "react-native-linear-gradient": "react-native-community/react-native-linear-gradient",
    "react-native-maps": "^0.24.2",
    "react-native-responsive-screen": "^1.2.2",
    "react-native-svg": "^9.5.2",
    "react-native-svg-transformer": "^0.13.0",
    "react-native-vector-icons": "^6.5.0",
    "react-native-vertical-tab-view": "^0.1.3",
    "react-navigation": "^3.11.0",
    "react-redux": "^7.1.0",
    "redux": "^4.0.1"
  },
  "devDependencies": {
    "@babel/core": "7.4.5",
    "@babel/plugin-proposal-decorators": "^7.4.4",
    "@babel/runtime": "7.4.5",
    "babel-jest": "24.8.0",
    "babel-plugin-transform-decorators-legacy": "^1.3.5",
    "jest": "24.8.0",
    "metro-react-native-babel-preset": "0.54.1",
    "react-test-renderer": "16.8.3",
    "redux-devtools": "^3.5.0"
  },
  "jest": {
    "preset": "react-native"
  }
}
Solution

  • You have to add plugin-proposal-decorators in babel.config.js

    module.exports = {
  presets: ['module:metro-react-native-babel-preset'],
  plugins: [['@babel/plugin-proposal-decorators', { legacy: true }]],
};

    Add "babel-preset-react-native": "4.0.0", and reset cache