Routing

Definition

Routing refers to determining how an application responds to a client request to a particular endpoint, which is a URI (or path) and a specific HTTP request method.

Explain Like I'm New

Routing is the hallway of doors in an office building. If a user walks in and wants to see their profile, the router directs them to the `/profile` door. If they want to delete an item, the router directs their `DELETE` request to the `/cart/delete` door.

Real World Example

Creating dynamic URL segments. When you visit `twitter.com/elonmusk`, 'elonmusk' isn't hardcoded into the server. The route is set up as `/users/:username`, and Express automatically extracts 'elonmusk' as a variable for you to look up in the database.

Common Use Cases

•API endpoint architecture
•Handling URL parameters and query strings

Interactive Example

Console output will appear here...

Interview Questions

basic

How do you capture dynamic variables in a URL like `/users/123`?

intermediate

What is the difference between `req.params` and `req.query`?

Flash Cards

Question

How to capture variables?

Click to reveal answer

Answer

Using a colon `:` in the route definition. E.g., `app.get('/users/:id')`. The value is then available inside `req.params.id`.

Question

req.params vs req.query?

Click to reveal answer

Answer

`req.params` grabs variables embedded directly in the path (e.g., `/users/:id`). `req.query` grabs optional variables appended to the end of the URL after a question mark (e.g., `/users?sort=desc`).