Configuring CORS
Cross-origin resource sharing (CORS) refers to a mechanism by which we can allow or disallow other domains from requesting restricted resources on a web page that are being served from a specific domain.
We have already set up a server on port 8080 of our localhost machine and we'll be also running a development server of the Angular CLI from another port in the next few chapters. Different ports on localhost are considered different origins, so we need to configure CORS in our Express.js server; otherwise, the requests from our Angular frontend will be disallowed.
Fortunately for us, configuring CORS in Express.js is easy. Head to your Terminal and run the following command from the root of the server folder to install the cors module:
npm install cors
Now, you need to open the src/index.ts file and import the cors module:
import cors from 'cors';
Next, add the following line just below where you created an instance...