Code reusability and modular design are what have made React one of the best JavaScript frameworks out there. Also, thanks to NPM, publishing a new JavaScript module has never been easier. All you need to do is point the main JavaScript file in your package.json
 and run npm publish

let create our own package

Plan

• initialize next project
• compile the project
• config package.json for deployement

Let go

• create a next project

npx create-next-app myapp -typescript

After creating our app, we need to add some features.
When we finish adding all features to our app, we need to publish it to NPM. We need a file named .npmignore it is similar to .gitignore, it is just to ignore some files and folder when we'll publish our package.

• add a .npmignore file

# https://docs.npmjs.com/misc/developers#keeping-files-out-of-your-package

#tests
test
coverage

#build tools
.travis.yml
.jenkins.yml
.codeclimate.yml

#linters
.jscsrc
.jshintrc
.eslintrc*

#editor settings
.idea
.editorconfig

• connect or create a NPM account

add this to package.json

{
    "files": [
        "/lib"
    ]
}

make shure this line your package is not private inside package.json "private": false,

• connect your project to npm

npm login

• after logged in pusblish to npm

npm publish

now your package is installed