I can't use new feature ES 2020 in my next.js app - reactjs

Question

I wanted to use a new feature of ES 2020 in my next.js so I used optional changes in my app. When I ran my code this error has occurred
Module parse failed: Unexpected token (50:191)
You may need an appropriate loader to handle this file type.
Then I ran this command
npm install --save-dev #babel/plugin-proposal-optional-chaining
but the problem still exists.
Then I decided to update babel/core to version 7, I updated it via this command
npx babel-upgrade --write
but the loader error still there and I don't have any idea. Here is my package.json file:
{
"name": "Karan",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"dev": "SET NODE_ENV=development && SET PORT=3001 && node server.js",
"build": "next build",
"prod-build": "next build",
"start": "SET NODE_ENV=production && SET PORT=8080 && node server.js"
},
"keywords": [],
"author": "",
"license": "ISC",
"dependencies": {
"#ckeditor/ckeditor5-basic-styles": "^11.1.4",
"#ckeditor/ckeditor5-build-classic": "^12.4.0",
"#ckeditor/ckeditor5-font": "^11.2.2",
"#ckeditor/ckeditor5-paragraph": "^11.0.5",
"#ckeditor/ckeditor5-react": "^1.1.3",
"#fullpage/react-fullpage": "^0.1.17",
"#sentry/browser": "^4.6.6",
"#svgr/webpack": "^4.3.2",
"#zeit/next-css": "^1.0.1",
"#zeit/next-stylus": "^1.0.1",
"axios": "^0.18.1",
"express": "^4.17.1",
"global": "^4.4.0",
"jalaali-js": "^1.1.0",
"leaflet": "^1.5.1",
"moment-jalaali": "^0.8.3",
"moment-jalali": "^0.3.9",
"next": "^8.1.0",
"next-images": "^1.1.2",
"next-routes": "^1.4.2",
"npm": "^6.12.1",
"numeral": "^2.0.6",
"persianjs": "^0.4.0",
"pm2": "^3.5.1",
"prop-types": "^15.6.2",
"qs": "^6.8.0",
"react": "^16.9.0",
"react-bootstrap-star-rating": "^3.5.5-alpha.0.3",
"react-dom": "^16.9.0",
"react-leaflet": "^2.4.0",
"react-modal": "^3.9.1",
"react-paginate": "^5.2.4",
"react-persian-calendar": "^1.0.3",
"react-rating": "^2.0.4",
"react-redux": "^5.0.7",
"react-responsive": "^5.0.0",
"react-select": "^2.4.4",
"react-share": "^2.4.0",
"react-slick": "^0.23.1",
"react-star-ratings": "^2.3.0",
"react-toastify": "^4.3.0",
"redux": "^4.0.4",
"redux-devtools-extension": "^2.13.5",
"redux-logger": "^3.0.6",
"redux-thunk": "^2.3.0",
"stylus": "^0.54.5"
},
"devDependencies": {
"#babel/core": "^7.0.0",
"#babel/plugin-proposal-optional-chaining": "^7.9.0",
"cross-env": "^5.2.1",
"optimize-css-assets-webpack-plugin": "^5.0.3",
"poststylus": "^1.0.0"
}
}

Answer 1

Since i see that you are using next you need to add a .babelrc file beside your package.json and include the below content -
{
"presets": ["next/babel"],
"plugins": []
}
next/babel includes
preset-env
preset-react
preset-typescript
plugin-proposal-class-properties
plugin-proposal-object-rest-spread
plugin-transform-runtime
styled-jsx
An alternative approach would be to add something similar (including the preset/transforms you need for your application) in your package.json
,
"babel": {
"presets": [
"nano-react-app"
],
"plugins": [
[
"#babel/plugin-proposal-class-properties",
{
"loose": true
}
],
[
"#babel/plugin-transform-react-jsx",
{
"pragmaFrag": "React.Fragment"
}
]
]
}