Clarification: How to add the customize package inside my app in react-native

In your case, once you have modified npm package once you have to reinstall all packages and your changes are not be saved because you are installing dependency from GitHub repository. So anyway you have two options to edit npm package and save it.

1. Copy code from the original repository and make your own component inside your re-usable components folder. ( Before copy whole code read the license of selected package )
2. Simply you can fork the original repository to your github account and after that you can make changes to forked repository.

Personally I choose Second (2) option instead of First one

STEPS

• Fork from the original repository

• After that make clone of this forked repo to your machine and change whatever you need (Here styles).

• After changing push the changes and commit into your forked repo

• After that you need to remove old original package from your dependency

npm uninstall --save react-native-floating-action

• After that install forked repo by this command

npm install git+https://[email protected]/myRepo/angular-translate.git

• Instead of https://[email protected]/myRepo/angular-translate.git add your forked project URL here

You can write a custom script using JavaScript which capable of replace, delete and add lines.

NPM automaticly execute postinstall after npm install command. You need to put your custom script in postinstall within package.json. For an example:

package.json:

{
    "name": "my_package",
    "description": "",
    "version": "1.0.0",
    "main": "index.js",
    "scripts": {
      "test": "echo \"Error: no test specified\" && exit 1",
      "fix:issue": "node ./scripts/issue.js",
      "postinstall": "npm run fix:issue"
    },
    "repository": {
      "type": "git",
      "url": "https://github.com/ashleygwilliams/my_package.git"
    },
    "keywords": [],
    "author": "",
    "license": "ISC",
    "bugs": {
      "url": "https://github.com/ashleygwilliams/my_package/issues"
    },
    "homepage": "https://github.com/ashleygwilliams/my_package"
  }

1. Keep your copy on root project folder or anywhere you prefer.
2. yarn remove <current package name in package.json>.
3. If this is native library, run pod install again for iOS.
4. yarn add file:/path-to-local-edited-package-folder
5. Rest of the steps will work same (pod install, etc)

Another approach as you mentioned (I don't suggest it as native libraries might not be removed completely)

1. Remove package from package.json.
2. On package.json file "library name same as current": "./<path to your folder>" or any other location.
3. yarn install