when should you use yarn and npm code example

Example: npm install yarn equivalent

npm install 'pckg-name'   -> yarn add 'pckg-name'
npm uninstall 'pckg-name' -> yarn remove 'pckg-name'
npm run 'your-script'     -> yarn run 'your-script'
npm init 				  -> yarn init
npm install 			  -> yarn OR yarn install

## In yarn flags like: --save-dev --save are used the same way