What are the best practices for using CORS in Express?

What are the best practices for using CORS in Express?

When using CORS in Express, it's important to specify the origins you want to allow, use middleware properly, and handle preflight requests.

Can you explain how to set up CORS in an Express app?

Sure! You can use the cors package. First, install it with npm install cors, then use it as middleware in your app.

What should I do if I want to allow multiple origins?

You can pass an array of allowed origins to the cors middleware, like this: cors({ origin: ['http://example1.com', 'http://example2.com'] }).

Are there any security concerns I should be aware of?

Yes, be cautious about allowing all origins with *, as it can expose your API to security risks. Always specify trusted origins.