routes.md

How Express Routes Work Together in app.js and employeeRoutes.js

Let's break down how these two lines work together:

// in employeeRoutes.js
router.get("/", getAllEmployees);

// in app.js
app.use("/api/employees", employeeRoutes);

The Flow of an API Request

1. Base URL Registration (app.js)

   • app.use("/api/employees", employeeRoutes) registers the employeeRoutes module as middleware
   • It sets "/api/employees" as the base path for all routes defined in employeeRoutes.js
   • Any request that starts with "/api/employees" will be forwarded to the employeeRoutes handler

2. Route Handler (employeeRoutes.js)

   • router.get("/", getAllEmployees) defines a GET endpoint
   • The "/" path here is relative to the base path defined in app.js
   • When combined with the base path, this creates the full route: "/api/employees/"

Examples

When a GET request is made to http://localhost:5000/api/employees/:

1. Express first matches the base path "/api/employees" in app.js
2. The request is forwarded to employeeRoutes
3. Inside employeeRoutes.js, the "/" route matches
4. The getAllEmployees controller function is executed

When a POST request is made to http://localhost:5000/api/employees/

1. Express first matches the base path "/api/employees" in app.js
2. The request is forwarded to employeeRoutes
3. Inside employeeRoutes.js, the "/" route matches
4. The createEmployee controller function is executed

This modular approach allows for:

• Clean separation of routes into different files
• Logical grouping of related endpoints
• Easy maintenance and scaling of the API
• Consistent URL structure with common prefixes