Thee dependencies usefull in PERN stack:

Table of contents:

  1. corse - Connect/Express middleware
  2. helmet - Connect-style middleware
  3. pg - Non-blocking PostgreSQL client for Node.js


  • cors: this is the library we can use to help communicate between the react application and the express server. Use to do this via proxy in the react application.

To install corse use:

npm install cors


  • helmet: this is the security library that updates http headers, this is not a silver bullet, but it can help. Helment is connect-style middellware which is compatyble with framework like Express.

To install helmet use:

npm install helmet


  • pg: main library that is used to communitcate with our plsql database, without this library communication with the database will not be possible.

To install node-postgres use:

npm install pg


  1. node-postgres
  2. corse
  3. helmet